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The Weight Debate

The sources of risk factor information for general practitioners: is physical activity under-recognised?

Fiona Dupen, Adrian E Bauman and Rose Lin

MJA 1999; 171: 601-603
For editorial comment, see Caterson

Abstract - Introduction - Methods - Results - Discussion - Acknowledgement - References - Authors' details
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Abstract Objective: To identify and compare the amount of material on physical activity and the management of smoking, hypertension and hypercholesterolaemia in medical journals and magazines frequently read by general practitioners.
Method: Qualitative study assessing the total number of articles and advertisements to which Australian GPs are exposed in journals and medical magazines they are likely to read.
Results: Only 6% of articles about cardiovascular disease (CVD) risk factors in the Medline search and 5% in the medical magazine search discussed exercise prescription or how to start and maintain an exercise program. Most CVD risk factor articles were on the pharmacological treatment of hypertension (42%), followed by hypercholesterolaemia (32%) and smoking cessation (20%). A review of medical magazines found similarly ranked results, and a count of advertisements indicated 67% related to hypertension, 26% to hypercholesterolaemia and 7% to smoking cessation.
Conclusions: GPs are less well informed by the medical media about physical activity than about other traditional CVD risk factors, although the epidemiological evidence for their health benefits is similar. Strategies should be developed to inform doctors about the evidence of benefits from regular moderate physical activity, and for GPs to recommend exercise in most clinical encounters.

Introduction Over the past few decades, clear epidemiological evidence has emerged for the health benefits of moderate regular physical activity for all adults. Evidence that physical inactivity is at least as important as other cardiovascular risk factors is summarised in the recently published US Surgeon General's Report on physical activity and health,1 and elsewhere.2-4

Given the higher prevalence of inactivity, which approaches 50% of Australian adults, compared with smoking prevalence (around 25%) or hypertension (15%), it is arguable that physical activity has a leading role in primary and secondary disease prevention, and in contributing to total population health risk.2-4

There is evidence from meta-analysis that physical activity plays a central role in preventing coronary disease,5 and inactivity contributes to population risk more than hypertension, elevated cholesterol levels or obesity.4,6 This is now recognised for older adults,7 and is independent of comorbidity or other risk factors.8 For example, a recent cohort study suggested that people who were mildly overweight but regularly active had a much lower risk of all-cause mortality than those with normal weight but inactive, after adjustment for comorbidity.9

The plethora of benefits attributed to physical activity extends beyond cardiovascular disease (CVD) prevention. Various studies (summarised in detail elsewhere1,4) show that physical activity:

  • is an independent protective factor for overweight status;

  • is central to the primary prevention of non-insulin-dependent diabetes;10-12

  • increases high-density lipoprotein levels;

  • reduces mild essential hypertension;13

  • prevents colon cancer;14

  • is associated with reduced rates of injury and falls in the elderly;

  • is associated with some reduced risk of ischaemic stroke; and

  • improves some mental health outcomes, such as anxiety and depression.

The public health rationale for promoting physical activity is now impressive, but general practitioners are not as informed about advising patients to be active compared with the management of other cardiovascular risk factors.15,16 The qualitative study examines the sources and amount of physical activity information provided to GPs through medical journals and magazines. Our objective is to identify inequalities in the amount of information provided to GPs about physical activity in CVD risk-reduction strategies.

Methods Our specific aims were:

  • to determine whether GPs are exposed to information about physical activity in medical journals that they would be likely to read;

  • to compare the number of journal articles on physical activity with those on smoking cessation, hypertension and cholesterol management; and

  • to compare the number of advertisements in "medical trade" magazines regarding physical activity with those on the pharmacological treatment of smoking, hypertension and hypercholesterolaemia.

The study was divided into three parts: a Medline search and review of peer-reviewed articles in journals likely to be read by GPs, a review of articles in weekly medical magazines which target GPs, and a review of paid advertisements in journals and magazines.

Peer-reviewed journals
We searched Medline from 1987 to July/August 1997. The journals chosen for review were American Family Physician, Australian Family Physician, the British Journal of General Practice, the British Medical Journal, the Canadian Medical Association Journal, Family Medicine, Family Practice, the Journal of Family Practice, The Lancet, the Medical Journal of Australia, the New England Journal of Medicine, and The Practitioner. These comprised a non-random selection of journals which were of interest to GPs or to a general medical readership.

Key words used in our search were "physical activity", "exercise", "smoking", "tobacco", "hypertension", "high blood pressure", "cholesterol" and "lipid(s)". All abstracts were read to identify whether the orientation of the articles was towards pharmacological risk-factor reduction (antihypertensive medication, cholesterol-lowering medication), behavioural counselling or medical therapy for smoking cessation, or advice or behavioural counselling about physical activity. Journal articles were read to confirm the findings reported in the abstract.

Articles were counted if they met the following criteria:

For physical activity: articles that included the basic components of exercise prescription and advice (frequency, intensity, time), or behavioural counselling/behavioural change approaches to increasing physical activity among patients.

For smoking: articles that provided strategies for the promotion of quitting smoking, including behavioural counselling or pharmacological approaches to cessation.

For hypertension: articles that discussed trends or innovations in the pharmacological treatment and management of hypertension, or discussed non-pharmacological approaches.

For cholesterol: articles that discussed pharmacological treatment with cholesterol-lowering medication or provided detailed nutritional advice.

Letters were included separately in the count, using the same inclusion criteria.

Medical magazines
We manually searched Australian Doctor Weekly, Current Therapeutics, and the Medical Observer for articles published from 1987 to July/August 1997, using the same inclusion criteria as used for the Medline search. Letters were not included. This search included three of the five most-read journals and magazines by Australian GPs.17

Advertisements We manually searched the eight issues preceding August 1997 of Australian Doctor Weekly, Australian Family Physician, Current Therapeutics, the Medical Journal of Australia, and the Medical Observer, and counted the total number of advertisements about physical activity, and the pharmacological treatment of smoking, hypertension and hypercholesterolaemia.

Results

Peer-reviewed journals
From the peer-reviewed journals, 469 articles and 88 letters met the criteria for inclusion. Fewer articles were written about physical activity (6%) than about smoking cessation (20%), hypercholesterolaemia (32%) and hypertension (42%). Letters followed a similar pattern: physical activity, 3%; smoking, 25%; hypertension, 29%; and hypercholesterolaemia, 34% (Figure).

Medical magazines
We were able to retrieve about 95% of the issues of each medical magazine. Of 96 articles identified in this search, only 5% discussed exercise prescription or how to start and maintain an exercise program; 11% were about the treatment of smoking, 22% about hypercholesterolaemia, and 61% about the management of hypertension (Figure).

Advertisements
We found 240 advertisements that related to risk-factor reduction for CVD. None pertained to physical activity. Most advertisements (67%) were for the pharmacological treatment of hypertension, 26% were for cholesterol or lipid management, and 7% were for pharmacological approaches to smoking cessation.

Discussion A general medical readership appears to be less exposed to articles about physical activity than other risk factors. As articles about physical activity were counted even when not related to CVD, the proportionate share of articles about physical activity and CVD is even smaller than indicated in the Figure.

We studied a convenience sample of "typical" journals, but it is unlikely that other journals would show a different pattern. Readership surveys indicate that GPs are most likely to read Australian Doctor Weekly, Australian Family Physician, the Medical Observer, Current Therapeutics and Modern Medicine, in that order.17 All except the last of these were included in our qualitative review, and we included general practice and leading medical journals from other countries to demonstrate that this is not a phenomenon confined to an Australian readership. Thus, it appears that medical practitioners generally are less exposed to the evidence for physical activity and health, or to articles encouraging them to provide advice about this issue.

The epidemiological evidence for the health benefits of physical activity is now compelling, based on consistent findings across studies, and these are independent effects of activity.4,5,8-12 The evidence is strengthened by demonstrations that increases in physical activity or fitness confer subsequent reduced risk of death from all causes, even after as little as two years.8,18 Further, increasing fitness to a moderate level confers a benefit at any age, suggesting that it is never too late to start some physical activity.1,7,8

The prevalence of physical inactivity is high, with around half the population insufficiently active, even given the moderate level of current recommendations.19,20 This is a higher prevalence than that for tobacco smoking or hypertension, so the community health gains are likely to be substantial if overall activity levels could be increased. Progress towards the National Health and Medical Research Council (NHMRC) weight maintenance strategy could also be facilitated by increased physical activity.21

Careful inspection of the evidence suggests that the activity required for health may be more moderate than previously thought; there is no longer an absolute need for achieving "aerobic" or vigorous levels of activity. Current recommendations, expressed in the National Physical Activity Guidelines,19 include the "accumulation of at least 30 minutes of moderate activity on most days of the week" as the central focus, and making incidental and everyday activities more common (such as using the stairs or walking to local shops). This makes the goal of becoming sufficiently active more achievable.1,22

A number of possible reasons why physical activity is under-reported in the medical media can be proposed. First, physical activity may not be of interest for journals or doctors. It is a behaviour, requiring brief advice for all patients (as for smoking), and, if time permits, more detailed counselling and skills training. Doctors may perceive they have little time or insufficient skills for such counselling about activity levels.15,16 Another possible reason relates to clinical interest being driven by marketing forces, which means that pharmaceutical paradigms might predominate. There is little commercial benefit to be obtained from promoting moderate physical activity, so private sector sponsors are unlikely to materialise. Further, doctors are likely to attend educational sessions and programs sponsored by private sector companies, and expert- and clinician-driven agendas seem to place treatable risk factors most firmly on this educational agenda. This may drive editorial policy in this area, and appears to do so internationally.

Our data suggest the need for physical activity advocacy, not only by public health personnel, but also by journal editors and senior clinicians. There is a need to reposition physical activity commensurate with its importance as a risk factor for heart disease and diabetes, and as an evidence-based preventive approach for many other conditions. Medical practice is a central setting for physical activity advice.23 This means that the medical media in general, and clinical specialists in disciplines including cardiology, endocrinology, injury prevention and mental health, need to be more vigilant in recommending moderate activity, and encourage all doctors to advise their patients accordingly. This could lead to patients' becoming generally more active, and, by achieving recommended levels of activity, contributing to health gains for all Australians.


Acknowledgement
The authors were the recipients of a 1997 grant from the University of New South Wales School of Community Medicine Small Grants Scheme.

References
  1. United States Department of Health and Human Services. US Surgeon General's report: physical activity and health. Atlanta, Georgia: Centers for Disease Control, 1996
  2. Bauman A. The use of population attributable risk (PAR) in understanding the health benefits of physical activity. Brit J Sports Med 1998; 32: 279-280.
  3. McGinnis JM, Foege WH. Actual causes of death in the United States. JAMA 1993; 270: 2207-2212.
  4. Bauman A, Owen N. Physical activity of adult Australians: epidemiological evidence and potential strategies for health gain. J Sci Med Sport 1999; 2: 30-41.
  5. Berlin J, Colditz GA. A meta analysis of physical activity in the prevention of coronary heart disease. Amer J Epidemiol 1990; 132: 612-628.
  6. Haapanen-Niemi N, Vuori I, Pasanen M. Public health burden of coronary heart disease risk factors among middle-aged and elderly men. Prev Med 1999; 28: 343-348.
  7. Bijnen F, Caspersen CJ, Feskens EJM, et al. Physical activity and 10-year mortality from cardiovascular diseases and all causes -- the Zutphen Elderly Study. Arch Int Med 1998; 158: 1499-1505.
  8. Blair SN, Kohl HW, Barlow CE, et al. Changes in physical fitness and all cause mortality: a prospective study of healthy and unhealthy men. JAMA 1995; 273: 1093-1098.
  9. Lee CD, Jackson AS, Blair SN. US weight guidelines -- is it also important to consider cardiorespiratory fitness? Int J Obesity 1998; 22 Suppl 2: S2-S7.
  10. Helmrich S, Ragland DR, Paffenbarger RS. Prevention of non-insulin dependent diabetes mellitus with physical activity. Med Sci Sports Exercise 1994; 26: 824-830.
  11. Manson JE, Rimm E, Stampfler MJ, et al. Physical activity and the incidence of non-insulin dependent diabetes in women. Lancet 1991; 338: 774-778.
  12. Wei M, Gibbons LW, Mitchell TL, et al. The association between cardiorespiratory fitness and impaired fasting glucose and type 2 diabetes mellitus in men. Ann Intern Med 1999; 130: 89-96.
  13. Cleroux J, Feldman RD, Petrella RJ. Lifestyle modifications to prevent and control hypertension. 4. Recommendations on physical exercise training. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada. CMAJ 1999; 160 (9 Suppl): S21-S28.
  14. Colditz GA, Cannuscio CC, Grazier AL. Physical activity and reduced risk of colon cancer. Cancer Causes Control 1997; 8: 649-667.
  15. Bull FC, Jamrozik K. Advice on exercise from a family physician can help sedentary patients to become active. Am J Prev Med 1998; 15: 85-94.
  16. Bauman A, Mant A, Middleton L, et al. Health promotion -- a needs assessment of general practitioners. Med J Aust 1989; 151: 262-269.
  17. Medical publications readership survey 1998, conducted by Quadrant Research Sydney, for Medical Publishers Association, Sydney, 1998.
  18. Paffenbarger R, Hyde RT, Wing AL, et al. The association of changes in physical activity level and other lifestyle characteristics with mortality among men. N Engl J Med 1993; 328: 538-545.
  19. National Physical Activity Guidelines for Australians. Canberra: Active Australia and Commonwealth Department of Health and Aged Care, 1999.
  20. Abraham B, d'Espaignet ET, Stevenson C. Australian health trends 1995. Canberra: Australian Institute of Health and Welfare, 1995.
  21. Acting on Australia's weight. A strategic plan for the prevention of overweight and obesity. Canberra: National Health and Medical Research Council; 1997.
  22. Morris JN. Exercise in the prevention of coronary heart disease: today's best buy in public health. Med Sci Sports Exercise 1994; 26: 807-814.
  23. Bull FCL, Schipper ECC, Jamrozik K, Blanksby BA. How can and do Australian doctors promote physical activity? Prev Med 1997; 26: 866-873.

Authors' details School of Community Medicine, University of New South Wales, NSW.
Fiona Dupen, MSc, Research Assistant;
Adrian E Bauman, PhD, FAFPHM, Professor;
Rose Lin, MPH, Research Assistant.

Reprints will not be available from the authors.
Correspondence: Professor A Bauman, Epidemiology Unit, Locked Mail Bag 17, Liverpool Hospital, NSW 2170.
a.baumanATunsw.edu.au

©MJA 1999
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