Volume 172 Issue 8

Abstract Objectives: To compare rates of mortality from coronary heart disease (CHD) between populations living within and outside Australian capital city statistical divisions. Design and setting: Descriptive epidemiological study based on data for all residents of Australia aged 30-69 years who died between 1986 and 1996 in all States and Territories of Australia. Main outcome measures: Standardised mortality rates from all causes and coronary heart disease as coded by the Australian Bureau of Statistics, and estimated excess deaths in populations living outside capital city statistical divisions. Results: Between 1986 and 1996, mortality from CHD declined by 46% in men and 51% in women, and accounted for 61% of the decline in mortality from all causes in men and 48% in women. More deaths than expected from acute myocardial infarction resulted in mortality rates from CHD up to 30% higher in men and 21% higher in women living outside the capital city statistical divisions, and accounted for an overall estimated excess of 3835 deaths from CHD in men (32% of excess deaths from all causes), and 1385 deaths from CHD in women (27% of excess deaths from all causes) over the 11-year study period. Conclusions: Although there were impressive declines in coronary mortality in all Australian States and Territories from 1986 to 1996, populations living outside capital cities continue to have higher death rates from CHD. These differences in mortality rates indicate a need for further research into factors which may influence mortality rates for CHD in rural and remote areas, and immediate measures to ensure optimal treatment of coronary risk factors and acute coronary events in such populations. Coronary heart disease (CHD) remains the largest single cause of death in Australia.1 Although there has been a steady decline in the death rate associated with CHD over the past 30 years, rates of decline have not been equal throughout Australia.2,3 A study of coronary mortality in Tasmania showed higher rates of mortality outside the capital city region.4 We examined official data for Australian men and women aged 30-69 years between 1986 and 1996 for evidence of differences in rates of death from CHD between capital city and regional populations. Methods The Australian Bureau of Statistics (ABS) collects and disseminates social, demographic and economic statistics for 66 Statistical Divisions based on an Australian Standard Geographical Classification (ASGC).5 The boundaries of capital city statistical divisions are determined by the anticipated development of the city for a period of at least 20 years, and delimit an area that is stable for general statistical purposes. Statistical divisions outside a capital city are relatively homogeneous regions characterised by identifiable social and economic links between the inhabitants and between the economic units within the region, under the unifying influence of one or more major towns or cities. We obtained ABS estimates of the size of the Australian population aged 30-69 years, and its distribution between capital city and other statistical divisions for the years 1986 and 1996. We also obtained ABS data for mortality from all causes, and from CHD, acute myocardial infarction (AMI) and subacute and chronic myocardial ischaemia for men and women aged 30-69 years living within and outside capital city statistical divisions for each year from 1986 to 1996. We excluded deaths at 70 or more years because certification of the cause of death in older people may be unreliable.6 We defined mortality from CHD as deaths with an underlying cause classified under rubrics 410, 411, 413 and 414 of the International classification of diseases, ninth revision (ICD-9-CM),7 with mortality from AMI classified under ICD-9-CM rubric 410, and mortality from subacute and chronic myocardial ischaemia classified under rubrics 411, 413, 414. Statistical methods Annual age-standardised rates for mortality from all causes, CHD, AMI and subacute and chronic myocardial ischaemia were calculated as follows: The number of deaths in each age group (30-39, 40-49, 50-59 and 60-69 years), coded to each cause of death category, were summed. Age-specific rates were calculated and then standardised with weightings obtained from Segi's "world population" (World Health Organization standard population).8 The normal approximation for the distribution was used to calculate 95% confidence intervals. For each State and the Northern Territory, we calculated expected numbers of deaths in each age group for populations living outside capital city statistical divisions by applying age-specific mortality rates from populations living within the capital city statistical division. Differences between the actual (observed) number of deaths and the expected number of deaths were then summed across 10-year age strata to give total expected numbers of deaths. Excess deaths were calculated as the difference between the sum of the observed and the sum of the expected number of deaths for all States and the Northern Territory. The population of the Australian Capital Territory living outside the Canberra Statistical Division was less than 0.1% of the total population of the ACT and was not included in the calculation. Results Population size and distribution Unpublished regional population data from the ABS estimated that, in 1986, there were 7 174 246 Australians aged 30-69 years, 64.4% of whom lived in capital city statistical divisions. The sex distribution in capital cities was 49.9% men and 50.1% women, compared with 51.0% men and 49.0% women outside capital cities. By 1996, the estimated population of Australians aged 30-69 years had increased to 8 793 107, 63.5% of whom lived in capital city statistical divisions. The sex distribution in capital cities was 49.8% men and 50.2% women, compared with 50.7% men and 49.3% women outside capital cities. Trends in mortality rates among men Between 1986 and 1996, mortality from all causes in all 30-69-year-old Australian men declined by 23%; this decline within capital city statistical divisions was 25%, compared with 21% among men living outside capital city statistical divisions (Box 1). Mortality from all causes in populations outside the capital cities remained higher than in capital city populations, with the difference increasing from 12% in 1986 to 18% in 1996. Between 1986 and 1996, mortality from CHD in Australian men aged 30-69 years declined by 46% and accounted for 61% of the decline in all-cause mortality. Mortality among men living within capital city statistical divisions declined by 49%, compared with 41% among men living outside capital city statistical divisions (Box 1). Mortality from CHD in populations outside the capital cities remained higher than in capital city populations, with the difference increasing from 13% in 1986 to 30% in 1996. Mortality from AMI among men living within capital city statistical divisions declined by 62%, compared with 50% among men living outside capital city statistical divisions (Box 1). Mortality from AMI in men living outside the capital cities remained higher than in capital city populations, with the difference increasing from 24% in 1986 to 63% in 1996. Excess mortality outside capital city statistical divisions Box 2 shows that, among men, CHD accounts for 32% of the excess deaths from all causes from 1986 to 1996 occurring outside the capital city statistical divisions. Among those deaths coded as CHD, observed deaths from AMI exceeded expected deaths by 5487. The number of excess deaths from CHD is smaller than that from AMI, as there was a higher rate of death from subacute and chronic myocardial ischaemia in capital city populations. Observed deaths from AMI among men aged 30-39 years living outside capital city statistical divisions exceeded expected deaths by 79%; corresponding figures for the remaining age groups were 72% (40-49 years), 51% (50-59 years), and 25% (60-69 years). Trends in mortality rates among women Between 1986 and 1996, mortality from all causes in all 30-69-year-old Australian women declined by 21%; this decline within capital city statistical divisions was 24%, compared with 18% among women living outside capital city statistical divisions (Box 1). Mortality from all causes in populations outside the capital cities remained higher than in capital city populations, with the difference increasing from 6% in 1986 to 15% in 1996. Between 1986 and 1996, mortality from CHD in Australian women aged 30-69 years declined by 51% and accounted for 48% of the decline in all-cause mortality. Mortality among women living within capital city statistical divisions declined by 54%, compared with 50% among women living outside capital city statistical divisions (Box 1). Mortality from CHD in populations outside the capital cities remained higher than in capital city populations, with the difference increasing from 13% in 1986 to 21% in 1996. Mortality from AMI among women living within capital city statistical divisions declined by 59%, compared with 54% among women living outside capital city statistical divisions (Box 1). Mortality from AMI in women living outside the capital cities remained higher than in capital city populations, with the difference increasing from 24% in 1986 to 38% in 1996. Excess mortality outside capital city statistical divisions Box 2 shows that, among women, CHD accounts for 27% of the excess mortality from all causes occurring outside the capital city statistical divisions. Observed deaths from AMI exceeded expected deaths by 1479. Observed deaths from AMI among women aged 30-39 years living outside capital city statistical divisions exceeded expected deaths by 108%; corresponding figures for the remaining age groups were 75% (40-49 years), 44% (50-59 years), and 20% (60-69 years). Overall mortality Box 3 shows that death rates from CHD outside capital cities are consistently higher than within capital cities in all Australian States and the Northern Territory, the only exception being mortality from CHD among women in the Northern Territory in 1986. Discussion The contribution of reduced CHD mortality to the overall decline in all-cause mortality in Australia from 1986 to 1996 was 61% for men and 48% for women. However, our findings show that CHD mortality rates were higher outside capital cities, and that discrepancies increased from 1986 to 1996 and were largest in younger age groups. It is likely that the differences we found in CHD mortality are real, as they are matched by parallel trends in all-cause mortality rates, and at least two studies have confirmed the validity of deaths coded by the ABS to CHD.9,10 While a study based on 1979 data questioned the validity of subcategories of CHD such as rubric 410 (AMI),11 we found consistently higher death rates from AMI in populations outside capital cities in all Australian States and the Northern Territory (data not shown), despite variations in medical certification requirements between States. The apparent higher rates of mortality in capital city populations from subacute and chronic CHD may be the result of a coding anomaly or of deaths occurring in large population centres after patients were moved there for the management of their subacute or chronic CHD. Our study was limited to documenting the difference in CHD mortality between capital cities and other areas. Clearly, an understanding of the factors associated with higher CHD mortality outside capital cities has implications for prevention and improved treatment of CHD. This would require detailed examination of population characteristics to determine which populations outside capital cities, including subpopulations such as Indigenous people, are most at risk of higher mortality. It is also necessary to consider factors such as differences in socioeconomic status, in risk factors for CHD, and in access to medical care. Previous reports showed that the decline in mortality from CHD in NSW was slower in lower income populations, many of which were in rural or regional areas.12,13 Also, sudden cardiac death in Tasmanian men was found to occur twice as frequently in unemployed men compared with employed men.14 While the association between populations with lower socioeconomic status and higher risk for CHD is recognised, the actual factors that influence this association have not been well delineated. Risk factors for CHD clearly have an influence on mortality. Much of the decline in mortality from CHD in Finland from 1972 to 1992 can be explained by changes in the three main coronary risk factors: serum cholesterol level, blood pressure and smoking.15 In Australia, the National Heart Foundation (NHF) Risk Factor Prevalence Surveys found significant declines between 1980 and 1989 in the prevalence of hypertension and cigarette smoking, but no overall favourable trend in lipid levels.16 However, these surveys are limited to capital cities, and it is not known whether regional areas of Australia have seen the same trends in risk factor prevalence. In 1992, a major risk factor prevalence survey based on the 1989 NHF Risk Factor Prevalence Survey was undertaken in two rural regions of Tasmania. The prevalence of major coronary risk factors was consistent with the high rate of mortality from CHD among men in North-West Tasmania, but did not explain variation in rates of mortality in women across the three regions of Tasmania.17 Differences in mortality from CHD may be the result of differential incidences of CHD or differences in case-fatality rates. A detailed study of sudden cardiac death among previously asymptomatic men found that the higher rate of deaths in the two rural regions of Tasmania occurred mostly among men for whom symptomatic CHD could have been diagnosed, implying a higher case-fatality rate for CHD.14 This finding was supported by higher rates of coronary deaths occurring after hospitalisation in the two rural regions of Tasmania from 1986 to 1989,4 and in Newcastle in 1984.18 A higher case-fatality rate may result from differences in risk of death from factors such as previous infarction, delays in reaching medical care, or differences in medical care.19 While the relative geographic isolation of most populations outside the capital cities may be expected to result in delays in reaching secondary and tertiary medical centres, the findings of the MONICA study did not support changes in time to medical care (including ambulance staff) having a significant effect on deaths before hospitalisation in major population centres.18 A significant decline in case fatality after hospitalisation did, however, make an important contribution to the overall decline in coronary deaths in the MONICA centres of Auckland (New Zealand), Newcastle (Australia) and Perth (Australia) from 1984 to1993. Medical management of acute coronary events has changed substantially over the past 20 years. The use of aspirin, thrombolytic therapy and coronary angioplasty as first-line treatments for AMI has resulted in reductions in mortality of up to 43%.20,21 The use of thrombolytic therapy in the MONICA centres increased from being rare in the early 1980s, to being used in approximately 50% of hospitalised patients with non-fatal definite myocardial infarction or coronary death by the early 1990s.22,23 The benefits of such treatments are dependent on them being given soon after the event,24 and it is not clear whether populations living at any distance from secondary or tertiary medical centres experience delays in access to new treatment methods for symptomatic CHD. In southern Tasmania between 1992 and 1996, 849 doses of streptokinase and tissue plasminogen activator were administered for AMI. No thrombolytic therapy was administered outside the capital city of Hobart (Royal Hobart Hospital Pharmacy Supplies Report), despite 15% of the population of the Southern Region living outside the capital city and having mortality rates approximately 40% higher than the capital city population. In conclusion, although there have been impressive declines in mortality from CHD in all Australian States and Territories over the past 30 years, the 35% of the Australian population living outside the capital cities continue to have higher coronary mortality. Our results indicate the need for increased research into factors which may influence mortality rates for CHD in rural and remote areas. Acknowledgements This study was supported by funding from Roche Products Pty Ltd and the Tasmanian branch of the AMA, and by assistance in-kind from the Hobart City Council and Australian Hospital Care Ltd. We are grateful to Chris Sweeney from the Australian Bureau of Statistics and to the Pharmacy Department of the Royal Hobart Hospital. References Tonkin AM, Bennett S. Cardiovascular disease at the turn of the century. Med J Aust 1999; 170: 408-409. Gibberd RW, Dobson AJ, Florey C du Ve, Leeder SR. Differences and comparative declines in ischaemic heart disease mortality among sub-populations of Australia 1969-1978. Int J Epidemiol 1984; 13: 25-31. Sexton PT, Woodward DR, Gilbert N, Jamrozik K. Interstate differences in trends in coronary mortality and risk factors in Australia. Med J Aust 1990; 152: 531-534. Sexton PT, Jamrozik K, Walsh J, et al. Regional variation in coronary mortality within Tasmania. Med J Aust 1992; 157: 449-451. Australian Bureau of Statistics. Australian Standard Geographical Classification. Canberra: ABS, 1998. Christie D. Mortality from cardiovascular disease. Med J Aust 1974; 1: 390-393. National Coding Centre, Faculty of Health Sciences, University of Sydney. Australian version of the international classification of diseases. 9th revision, clinical modification (ICD-9-CM). 2nd ed. Vol.1: Tabular list of diseases. Sydney: NCC, University of Sydney, July 1996. Doll R. Comparison between registers, age-standardised rates. IARC Sci Publ 1976; 3: 453-459. Martin CA, Hobbs MST, Armstrong BK. Estimation of myocardial infarction mortality from routinely collected data in Western Australia. J Chron Dis 1987; 40: 661-669. Sexton PT, Jamrozik K, Walsh J. Death certification and coding for ischaemic heart disease in Tasmania. Aust N Z J Med 1992; 22: 114-118. Dobson AJ, Gibberd RW, Leeder SR. Death certification and coding for ischaemic heart disease in Australia. Am J Epidemiol 1983; 117: 397-405. Burnley IH. Inequalities in the transition of ischaemic heart disease mortality in New South Wales, Australia. Soc Sci Med 1998; 47: 1209-1222. Taylor R, Chey T, Bauman A, Webster I. Socio-economic, migrant and geographic differentials in coronary heart disease occurrence in New South Wales. Aust N Z J Public Health 1999; 23: 20-26. Sexton PT, Jamrozik K, Walsh J. Sudden unexpected cardiac death among Tasmanian men. Med J Aust 1993; 159: 467-470. Vartiainen E, Puska P, Pekkanen J, et al. Changes in risk factors explain changes in mortality from ischaemic heart disease in Finland. BMJ 1994; 309: 23-27. Bennett SA, Magnus P. Trends in cardiovascular risk factors in Australia. Results from the National Heart Foundation's Risk Factor Prevalence Study, 1980-1989. Med J Aust 1994; 161: 519-527. Thomson A, Rundle S, Singh BB, et al. Regional differences in cardiovascular risk factor prevalence in Tasmania: are they consistent with the increased cardiovascular mortality. Aust N Z J Med 1995; 25: 290-296. Beaglehole R, Stewart AW, Jackson R, et al. Declining rates of coronary heart disease in New Zealand and Australia, 1983-1993. Am J Epidemiol 1997; 145: 707-713. Beaglehole R. Medical management and the decline in mortality from coronary heart disease. BMJ 1986; 292: 33-35. Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto Miocardico (GISSI). Effectiveness of intravenous thrombolytic treatment in acute myocardial infarction. Lancet 1986; 1: 397-402. Second International Study of Infarct Survival Collaborative Group. Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17 187 cases of suspected acute myocardial infarction: ISIS-2. Lancet 1988; 2: 349-360. Doggen CJM, van der Palen J, Beaglehole R. Trends in medical management of acute myocardial infarction. N Z Med J 1993; 106: 278-281. Dobson AJ, Jamrozik KD, Hobbs MST, et al. Medical care and case fatality from myocardial infarction and coronary death in Newcastle and Perth. Aust N Z J Med 1993; 23: 12-18. Bett JHN. LATE assessment of thrombolytic efficacy with alteplase (rt-PA) six-24 hours after onset of acute myocardial infarction. Aust N Z J Med 1993; 23: 745-748. (Received 23 Sep 1999, accepted 31 Jan 2000) Authors' details The Hobart Private Hospital, Hobart, TAS. Peter T Sexton, PhD, FAFPHM, Director of Medical Services; Tiina-Liisa H Sexton, BCom, CA, Research Assistant. Reprints: Dr P T Sexton, The Hobart Private Hospital, Cnr Argyle and Collins Streets, Hobart, TAS 7000. 1: Comparison of mortality rates between populations aged 30-69 years living within and outside capital cities in Australia Back to text 2: Estimated excess deaths from all causes, CHD and AMI among men and women living outside capital city statistical divisions from 1986 to 1996 Age group (years) 30-3940-4950-5960-69Total Men Mortality from all causes Observed deaths8599126982622760856108380 Expected deaths736310718216195672596425 Excess deaths123619804608413111955 Mortality from CHD (ICD-9-CM 410, 411, 413, 414) Observed deaths682270372391824128865 Expected deaths493209959021653625030 Excess deaths189604 133717053835 Mortality from AMI (ICD-9-CM 410) Observed deaths470197253341328721063 Expected deaths263114435411062815576 Excess deaths207828 179326595487 Women Mortality from all causes Observed deaths38877021138633146756238 Expected deaths32025998119722991851090 Excess deaths6851023189115495148 Mortality from CHD (ICD-9-CM 410, 411, 413, 414) Observed deaths143537 187869379495 Expected deaths91381 150361358110 Excess deaths52156 3758021385 Mortality from AMI (ICD-9-CM 410) Observed deaths102391 140050736966 Expected deaths49223 97242435487 Excess deaths53168 4288301479 CHD=coronary heart disease. AMI=acute myocardial infarction Back to text 3: Mortality within and outside capital city statistical divisions by Australian States and Territories Men Age-standardised mortality rate per 100000 (95% CI) % changeEstimated excess 1986 1996 per yeardeaths from CHD All causesCHDAll causesCHDfrom CHD1986-1996 New South Wales Capital722 (702-741)223 (212-234)511 (496-527)106 (99-113)-4.8 Balance761 (736-786)232 (218-246)601 (581-622)143 (133-153)-3.51506 Victoria Capital658 (638-678)199 (188-210)487 (470-503)97 (90-105)-4.7 Balance755 (722-789)242 (223-261)583 (556-611)131 (118-144)-4.21015 Queensland Capital691 (657-724)226 (207-245)549 (523-575)122 (109-134)-4.2 Balance754 (723-785)227 (210-245)585 (562-609)136 (125-147)-3.6444 South Australia Capital653 (619-687)213 (194-232)528 (499-557)125 (110-139)-3.8 Balance707 (650-764)234 (201-267)633 (583-683)160 (135-186)-2.9291 Western Australia Capital638 (603-673)183 (164-202)498 (471-525)102 (89-114)-4.0 Balance779 (716-841)249 (214-285)594 (546-642)121 (100-143)-4.7203 Tasmania Capital605 (526-684)141 (103-179)595 (520-669)102 (71-133)-2.5 Balance758 (685-831)276 (232-320)619 (558-680)144 (115-174)-4.3243 Northern Territory Capital640 (463-817)115 (46-185)716 (569-863)97 (36-158)-1.4 Balance1443 (1206-1679)233 (138-329)1030 (862-1199)132 (73-191)-3.9133 Australian Capital Territory 598 (521-675)205 (159-251)428 (372-484) 111 (82-140)-4.2 All of Australia Capital679 (668-690)209 (203-215)510 (501-519)107 (103-111)-4.4 Balance763 (747-778)237 (228-245)602 (590-614)139 (133-145)-3.83835 Women Age-standardised mortality rate per 100000 (95% CI) % changeEstimated excess 1986 1996 per yeardeaths from CHD All causesCHDAll causesCHDfrom CHD1986-1996 New South Wales Capital391 (377-405)82 (76-88)284 (273-296)32 (28-36)-5.5 Balance420 (401-439)89 (80-97)335 (319-350)45 (39-51)-4.5564 Victoria Capital360 (346-375)65 (59-72)274 (262-286)31 (27-35)-4.8 Balance361 (338-384)68 (58-77)307 (287-327)35 (28-41)-4.4277 Queensland Capital371 (347-395)67 (57-78)308 (288-328)39 (32-46)-3.8 Balance378 (355-400)75 (65-85)299 (282-316)36 (30-42)-4.7171 South Australia Capital347 (323-371)69 (58-79)285 (264-306)31 (24-38)-5.0 Balance291 (317-400)83 (64-103)339 (301-377)39 (26-52)-4.8143 Western Australia Capital349 (324-374)59 (49-70)275 (255-295)37 (30-45)-3.4 Balance386 (339-433)78 (296-372)334 (57-99)36 (24-49)-4.9105 Tasmania Capital424 (360-488)68 (42-93)365 (308-422)49 (28-70)22.5 Balance421 (367-475)87 (62-111)385 (336-434)54 (36-72)-3.462 Northern Territory Capital434 (271-597)46 (-10-103)392 (261-523)41 (-3-86)-1.0 Balance911 (702-1120)37 (-6-81)762 (593-932)88 (28-148)+12.563 Australian Capital Territory 380 (319-440)56 (32-80)267 (223-311)41 (23-59)-2.4 All of Australia Capital372 (363-380)71 (68-75)284 (278-291)33 (31-36)-4.9 Balance396 (384-407)80 (75-85)326 (317-335)40 (37-44)24.51385 CHD=coronary heart disease. Capital=within capital city statistical divisions. Balance=outside capital city statistical divisions. Back to Text

Peter T Sexton · Tiina-Liisa H Sexton

Medicine and the Community Who's overweight? Comparison of the medical definition and community views Susan M Donath MJA 2000; 172: 375-377 Abstract - Methods - Results - Discussion - References - Authors' details - - More articles on Public and environmental health Abstract Objective: To investigate the extent to which people who are medically defined as overweight perceive themselves to be overweight. Design: Secondary data analysis of the National Health Survey and the National Nutrition Survey conducted by the Australian Bureau of Statistics in 1995. Participants: 10 652 people aged 18 years and over (5076 men, 5576 women) in a multistage cluster sample of households throughout Australia. Main outcome measures: Body mass index (BMI) based on measured height and weight; self-reported perception of body weight (underweight, acceptable weight, or overweight) Results: Among people with a measured BMI ≥ 25, 49.3% of men (95% CI, 48.1%-50.5%) and 72.0% of women (95% CI, 70.8%-73.1%) considered themselves overweight. Among those with a measured BMI < 25, 3.4% of men (95% CI, 2.8%-4.1%) and 12.4% of women (95% CI, 11.4%-13.3%) considered themselves overweight. Older women were less likely to perceive themselves as overweight than younger women. The lowest BMI at which at least half the respondents considered themselves overweight was 26 to < 27 for women aged 18-59 years, and 28 to < 29 for older women and men. Conclusion: For many people, particularly men and older women, the meaning of "overweight" differs from the medical definition. Clinical and public health weight reduction programs which do not take this into account are unlikely to be successful. Overweight and obesity are key preventable risk factors for many diseases, particularly hypertension, cardiovascular disease and non-insulin-dependent diabetes.1 In Australia in 1995, the National Nutrition Survey found that 64% of men and 49% of women aged 18 and over were overweight or obese (using the standard definitions of the National Health and Medical Research Council [NHMRC]).2Despite this, the NHMRC expert report on prevention of obesity and overweight1 found few population-based data on Australians' weight-control behaviours. As the report noted, to understand weight-control behaviours, it is first necessary to answer the question: "Who perceives themselves as overweight?".1 To date, no national Australian studies have addressed this question. Most Australian studies of weight-control attitudes and behaviours have used small and unrepresentative samples and have focused on women, particularly younger women.3 Although two studies used larger, representative samples of adults in Adelaide and Melbourne to investigate the relationship between body mass index (BMI) and perceptions of overweight,4,5 both calculated BMI from self-reported height and weight. Self-reported measures are known to lead to underestimates of BMI.6-8 The 1995 National Health Survey9 and National Nutrition Survey10 provided a unique opportunity to investigate the relationship between Australian adults' subjective perceptions of their weight and their measured BMIs. I used data from these surveys to investigate: to what extent Australian adults with different BMIs perceive themselves to be overweight; and the BMI at which adults perceive themselves to be overweight. Methods The study was a secondary analysis of data from the National Health Survey9 and the National Nutrition Survey10 conducted by the Australian Bureau of Statistics in 1995. Data sources The 1995 National Health Survey was conducted on a multistage, cluster sample of households in all States and Territories of Australia. Information was obtained by personal interview. This study analyses responses to the question: "Do you consider yourself to be acceptable weight, underweight, or overweight?". The 1995 National Nutrition Survey was conducted on a random subsample of the households interviewed for the National Health Survey. Participants in the National Nutrition Survey answered detailed questions about their current food consumption and had their heights and weights measured by specially trained interviewers two to three weeks after the National Health Survey interview.10 Response rates were 97% for the National Health Survey9 and 61% for the National Nutrition Survey.10 Non-responders were more likely to be characterised by one or more of the following: high income, older than 59, unmarried, or unemployed. The current study was based on a sample of 5076 men and 5576 women aged 18 and over for whom height and weight measurements were obtained by the National Nutrition Survey. The sample represents 98.4% of respondents (excluding pregnant women). Data analysis Unit record data, containing detailed information on each person in the sample, were analysed using SPSS11 and Excel.12 The BMI of each person was calculated from measured height and weight (where BMI = ratio of body weight in kilograms to height in metres squared). Overweight was defined as a BMI of 25 or over and obesity as a BMI over 30.1,13 These cutoff points were derived from evidence of the association between BMI and mortality.14Population percentages were estimated from sample percentages using the weighting factors and methods of the Australian Bureau of Statistics (ABS),15 which adjust for the sampling method (multistage, cluster sampling). This ensured that the percentages represented as far as possible the adult Australian population. For percentages close to or equal to zero, exact confidence intervals were calculated using the binomial distribution.16 All other confidence intervals were estimated using the relative standard errors provided by the ABS.2 Results An estimated 64.5% of men and 49.2% of women had a BMI ≥ 25.2 Estimated percentages in each age group are shown in Box 1; percentages increased with age in both sexes until the ages of 50-54 years (men) and 55-59 years (women), and then remained stable or declined slightly. Significantly more men than women had a BMI ≥ 25 in almost all age groups, although the difference was smaller in the age groups over 55 years. Among people with a BMI ≥ 25, an estimated 49.3% of men and 72.0% of women considered themselves overweight (95% CIs, 48.1%-50.5% and 70.8%-73.1%, respectively). Estimated percentages of those who considered themselves overweight are shown in Box 2 by age group. At all ages, women were more likely to consider themselves overweight than men; the difference was significant for all except those aged 70 years and over. Women in this age group were less likely to consider themselves overweight than younger women, while men in their 20s or those 80 years and over were less likely to consider themselves overweight than men of other ages. Among people with a BMI < 25, an estimated 3.4% of men and 12.4% of women considered themselves overweight (95% CIs, 2.8%-4.1% and 11.4%-13.3%, respectively). For men, there was little variation with age (Box 2), and, although there were statistically significant differences between some age groups for women, these differences were small. The estimated percentage of people who considered themselves overweight at each measured BMI is shown in Box 3. Data for men and women in different age groups were analysed separately. For men, there were no significant differences between age groups (not shown). For women, the only significant difference was between women aged under 60 and older women. The percentages of both sexes who considered themselves overweight increased with BMI; the lowest BMI at which at least half the respondents considered themselves overweight was 26 to < 27 for women aged 18-59 years, and 28 to < 29 for older women and men. Discussion This study found that relatively few Australian adults with a BMI less than 25 considered themselves overweight, but that a large proportion of people who were overweight or obese considered their weight to be acceptable. This applied to half of the overweight men and a quarter of the overweight women. A potential limitation of the study was the response rate to the National Nutrition Survey, which was low by ABS standards for household surveys. However, adjustment of results to represent the total population would be expected to minimise the effect of response bias. The results of this study contrast with those of two other Australian studies.4,5 These found that around 25% of men and 45% of women of acceptable weight considered themselves overweight, while only about 15% of overweight men and 5% of overweight women considered their weight to be acceptable. Both earlier studies estimated BMI from self-reported height and weight, which are known to underestimate BMI.6-8 For example, based on self-reported height and weight, 36% of women and 52% of men aged 18 and over were overweight or obese in Australia in 1995,14 considerably fewer than the 49% of women and 64% of men found to be overweight or obese by measurement in the National Nutrition Survey.2 Therefore, in the earlier studies, some people classified as having acceptable weight would have been overweight, and those classified as overweight would mostly have had BMIs well in excess of 25. In addition, when respondents in the earlier studies were asked to assess their weight, they were given the choice of "slightly overweight",4,5 "very overweight"4,5 or "extremely overweight"4 (rather than the single option of "overweight" used in the current study). The option "slightly overweight" was chosen by nearly all who considered themselves overweight but were actually of acceptable weight, and by well over half those who considered themselves overweight and were actually overweight or obese. Thus, another possible explanation for the difference in my results is that, when given the choice of classifying oneself as "acceptable weight" or "overweight", those who consider themselves slightly overweight generally opt for "acceptable weight". The results of this study suggest that, for men and for women aged 60 and over, the meaning of "overweight" differs considerably from the medical definition. For men, "overweight" appears to mean a BMI greater than 28. Only a minority of men consider themselves overweight at lower BMIs, while 30% of men with a BMI of 30-31 consider their weight acceptable. This is consistent with the findings of a recent study of weight-control practices of adults in an Australian rural community; when asked about their weight goals in the next year, only one in five overweight men wished to attain a BMI below 25.17 Some highly muscular men may have a BMI above 25 and not be overweight, but, given the increase in BMI with age, this group is likely to be small. Men's perceptions may be influenced by the high proportion who are overweight; it is so common that being moderately overweight may be seen as normal. For women aged 60 and over, the meaning of "overweight" appears similar to that for men, but for younger women, the meaning is closer to the medical definition. However, for many of these younger women, a BMI in the upper part of the acceptable range constitutes being "overweight". A factor influencing these women's attitudes may be the mass media focus on images of very thin (young) women. The difference in attitudes between women of different ages may reflect a change in attitude with age; as a substantial proportion of older women are overweight, older women may consider it normal. There may also be a generational difference in women's attitudes, possibly related to changes in media images of the ideal female form. For most people, achieving and maintaining weight loss involves considerable lifestyle change, which is unlikely to be achieved unless people consider the reasons are compelling. My study suggests that, for clinical and public health weight reduction programs to be successful, they must first convince many overweight people that their weight is an issue which needs addressing. References National Health and Medical Research Council. Acting on Australia's weight: A strategic plan for prevention of overweight and obesity. Canberra: AGPS, 1997. Australian Bureau of Statistics. National Nutrition Survey: selected highlights, Australia, 1995. Canberra: AGPS, 1995. (Catalogue No. 4802.0.) Crawford D, Owen N. The behavioural epidemiology of weight control. Aust J Public Health 1994; 18: 143-148. Crawford D, Worsley A. Present and desired body weights of Australian adults: a cause for concern? Community Health Stud 1987; 11: 62-67. Paxton S, Sculthorpe A. Weight-loss strategies and beliefs in high and low socioeconomic areas of Melbourne. Aust J Public Health 1994; 18: 412-417. Hill A, Roberts J. Body mass index: a comparison between self-reported and measured height and weight. J Public Health Med 1998; 20: 206-210. Kuskowska Wolk A, Bergstrom R, Bostrom G. Relationship between questionnaire data and medical records of height, weight and body mass index. Int J Obes Relat Metab Disord 1992; 16: 1-9. Nieto Garcia FJ, Bush TL, Keyl PM. Body mass definitions of obesity: sensitivity and specificity using self-reported weight and height. Epidemiology 1990; 1: 146-152. Australian Bureau of Statistics. National Health Survey: users' guide. Canberra: AGPS, 1995. (Catalogue No. 4363.0.) Australian Bureau of Statistics. National Nutrition Survey: users' guide. Canberra: AGPS, 1995. (Catalogue No. 4801.0.) SPSS Inc. SPSS. Release 9.0.1. Chicago, Ill: SPSS Inc, 1999. Microsoft. Excel 97 SR-1. Microsoft, 1997. National Health and Medical Research Council. Reports of the 98th and 100th sessions. Canberra: AGPS, 1984 and 1985. Australian Bureau of Statistics. How Australians measure up. Canberra: AGPS, 1998. (Catalogue No. 4359.0.) Australian Bureau of Statistics. National Nutrition Survey: technical paper for confidentialised unit record file. Canberra: AGPS, 1995. (Catalogue No. 4807.0.) Armitage P, Berry G. Statistical methods in medical research. Oxford: Blackwell, 1994. Crawford D, Owen N, Broom D, et al. Weight control practices of adults in a rural community. Aust N Z J Public Health 1998; 22: 73-79. (Received 9 Sep 1999, accepted 16 Feb 2000) Authors' details Key Centre for Women's Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, VIC. Susan M Donath, BSc, MA, Lecturer. Reprints will not be available from the author. Correspondence: Ms S M Donath, Key Centre for Women's Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC 3052. s.donathATkcwh.unimelb.edu.au Make a comment Back to text Back to text Back to text

Susan M Donath

Personal Perspectives Perspectives from a surgeon turned hospital chaplain Irwin B Faris MJA 2000; 172: 389-391 At the end of January 1999, I retired from my chair of surgery to study theology full time as a candidate for ordination. The change from surgery to theology has been an interesting experience, and I have been pleased at how many of my clinician's skills are directly transferable to my new calling (eg, my ability to deal with people and my knowledge of the ways organisations function). As part of my training in 1999, I undertook a placement in the chaplaincy department of a teaching hospital. I chose this placement quite deliberately for two reasons: it was a hospital where I was unknown, except to some of the surgeons, and it gave me a chance to see a hospital from a totally different perspective from my accustomed one. I believe many doctors would be helped by greater understanding and awareness of the emotional responses of doctor and patient My first impression was how poor were the facilities in many wards. Some wards of special units had been renovated and were quite pleasant and well appointed. Other wards, notably those in the general medical and surgical units, with their high turnover and sick patients, were old and run-down with dingy paintwork and corridors cluttered with equipment. My sense from talking to the staff is that the stresses of working in these wards are considerable, and I could not escape the feeling that patients and staff deserve better in a rich country like ours. The next step was obtaining permission to visit patients. The medical students I have taught have complained from time to time of being refused permission by ward clerks and nursing staff to visit patients. I now have first-hand experience of this -- one ward clerk insisted on asking each patient if they wanted to be visited by a chaplain (access to the patients was easier on the days she was away). However, in most wards, access to patients was easier, particularly when I became known to the staff. It was particularly rewarding when a nurse would say, "Mr X is looking forward to seeing you" or "Mrs Y has some problems at home she might want to tell you about". My contact with patients was very enjoyable. I was surprised and delighted at how often and how readily patients would begin to tell me their life story. In my surgical practice, I prided myself on my ability to form a good relationship with my patients, but in this new role communication was on a much deeper level. There may be several explanations. A visit to a specialist, as I then was, can be quite daunting and, despite my best efforts, patients may have felt inhibited from talking openly. Alternatively, they may have believed (quite reasonably) that the detail was irrelevant to the purpose of the visit. Family doctors may have a different perspective, although I would be surprised if the interaction in a standard consultation is as deep as I experienced as a chaplain. I think a third explanation is most likely: in these visits, in contrast to most encounters with medical, nursing or ancillary staff, the patient was much more in control of the situation. There was no agenda (apart from my need to prepare a report for my supervisor), and patients could talk or not talk as they wished. The result was that almost all were happy to talk freely. Two insights caused me concern because they reflect poorly on our profession. The first was the frequency with which patients would tell me that they did not know what was going on with their treatment. I know the difficulty of communicating with sick patients and their families, particularly in the environment of a teaching hospital, and I know that patients have denied having had detailed explanations of planned procedures even when I have explained them myself. In practical terms, this highlights the need for reinforcement of what patients have been told and for testing of their understanding. It is not always easy to find opportunities for senior staff to talk to patients. It was my habit during the preoperative visit to ask patients if they had any further questions about their procedures. I was generally reassured by a negative response. However, this may have been false comfort if the patient did not understand what was to happen or was afraid to ask. Frequent use of written material given to the patient helped, but I think it would have been better had I directly tested the patient's understanding and provided additional information as needed. Nevertheless, there is another side: many patients take the view that the decision has been made, and the sooner the procedure is carried out the better; it may not be helpful to remind them that the carotid endarterectomy they are about to undergo carries a risk of stroke of about 2%, provided the information has been provided previously. The second issue, which disturbed me at times, was the frequency with which some chaplains expressed negative views of the medical profession. This may have been part of the syndrome "doctors are bastards, but my doctor is good". However, at times I heard sufficient detail of patients who had been hurt emotionally by their encounters with doctors to cause me concern about both our image and the way some of our colleagues appear to function. Although the patients seen by chaplains often have complex and difficult interactions of physical, emotional and spiritual factors, and are clearly not a random sample of the population, if these "difficult" patients are not being dealt with adequately by the medical profession, then we need to look to ways of improving the situation. During most of my time in the hospital, my background was unknown to the staff and patients. An exception, and a highlight of my time in the hospital, was when I took part in the teaching session to introduce a new group of medical students to the work of the chaplaincy. The object of the session was to point out the importance of spiritual factors in healing ("making whole"), and to claim on behalf of the chaplains to be the specialists in this area. My ability to talk to the students in familiar language may have enhanced their appreciation of this point of view. The program of training that I undertook is called Clinical Pastoral Education (CPE). Its aim is to allow non-ordained hospital chaplains and ordination candidates to "develop new awareness of their own humanity and of the needs of those to whom they minister".1 This is now an internationally recognised discipline, which began in the United States in the 1920s. The links with medical teaching go back to its originators, one of whom, Dr Richard Cabot, developed the case-study conference at the Massachusetts General Hospital (S Ames, Clinical Pastoral Educator, Anglican Centre for Clinical Pastoral Education, Melbourne, VIC, personal communication). As currently practised, the major element in CPE is the "verbatim" report, which purports to be a literal report of part of a clinical chaplain-patient encounter. This is written from memory and presented either to the supervisor or to the group, which typically comprises four to six students and two to three supervisors. This report is analysed and discussed in detail, often in a way which confronts students with their own feelings and inadequacies. As far as I can determine, this process has no parallels in medical education, either undergraduate or postgraduate. At least one aspect of the CPE program might be helpful in medical education and practice. I believe many doctors would be helped by greater understanding and awareness of the emotional responses of doctor and patient, which occur in almost every clinical encounter. As doctors, we are trained to act in a detached, "objective" manner with our patients. This may be a necessary part of clinical decision-making, but I suspect that doctors do respond emotionally to patients, often in ways we do not recognise or admit. Explicit acknowledgment of this would enable greater rapport with patients and their families, especially in times of stress. In addition, greater awareness of, and sensitivity to, the patient's feelings and emotions would probably help improve patients' perceptions of doctors. There are important lessons from this CPE program for all clinicians concerning communication with patients and families. The first is the need for reinforcement and testing of understanding in situations such as obtaining consent for procedures. The second is the recognition of emotional responses of patients and doctors to clinical encounters. A greater appreciation of these issues would improve the quality of our communication and enhance our image. Irwin B Faris MD, FRACS, Deacon, formerly Professor of Surgery The University of Melbourne The Geelong Hospital, Geelong, VIC ifarisATozemail.com.au Reprints will not be available from the author. Correspondence: Irwin B Faris, 1 Brendan Court, Highton, VIC 3216. Association for Supervised Pastoral Education in Australia. Standards for clinical pastoral education, 1995: 2. 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Irwin B Faris