eMJA: In Other Journals, 20 October 2008

Some medications used in the treatment of newly diagnosed chronic obstructive pulmonary disease (COPD) may increase the risk of mortality, according to US researchers. Over 145 000 patients with newly diagnosed COPD were followed for up to 5 years, during which 32 130 died. A large control group of over 320 000 people were matched to the case patients on the basis of sex, age, and year of diagnosis. Measurements included all-cause mortality, respiratory and cardiovascular deaths, and exposure to COPD medications. Theophylline was associated with an increased risk of respiratory death and ipratropium with a greater risk of cardiovascular death. Inhaled corticosteroids were associated with a reduced risk of cardiovascular death. The researchers point out that a limitation of their study is that potential confounders such as smoking status and severity of COPD were unknown. They call for more research to determine whether the observed associations reflect causal relationships.

A Mediterranean feast

The health benefits conferred by the Mediterranean diet have become well known, particularly in terms of prevention of cardiovascular disease and improved quality of life. The pattern of eating represents that usually consumed among people bordering the Mediterranean Sea — a diet rich in vegetables, fruits, legumes, cereals and fish, with a moderate intake of red wine during meals. Most studies have focused on adherence to the diet overall, rather than relating health benefits to individual nutrients, as this approach reflects actual eating habits more closely. A systematic review with meta-analysis of all available prospective cohort studies between 1966 and 2008 has confirmed that greater adherence to the Mediterranean diet is associated with significant improvement in health status. The cumulative analysis of 12 studies included over 500 000 individuals followed for a period of 3–18 years. Scores were attributed in each of these studies to estimate the degree of adherence to the diet. An increased score was significantly associated with a reduced risk of mortality overall, and a lower risk of death from cardiovascular disease and cancer. The incidence of Parkinson’s disease and Alzheimer’s disease was also reduced in those with greater adherence to the Mediterranean diet. The authors of the study comment that the findings are particularly clinically relevant in terms of public health, the production of guidelines for healthy lifestyles, and the prevention of major chronic diseases.

BMJ 2008; 337: a1344

CT vs colonoscopy

There is consensus that screening for colorectal cancer is effective, but adherence to guidelines may be suboptimal due to the perceived invasive nature of the procedures involved. The results of a US study assessing the accuracy of computed tomographic (CT) colonography suggest this less invasive test may be an adjunct to improve screening effectiveness. A group of over 2500 asymptomatic participants aged 50 years or older underwent CT colonography followed by optical colonoscopy and histological review of any lesions identified. CT colonography was found to have a sensitivity of 0.90 for large adenomas and cancers, meaning that the technique identified 90% of subjects with a lesion measuring 10 mm or more in diameter. The authors comment that CT colonography is a rapid, acceptable technique with few adverse effects, but that controversy surrounding its effectiveness is probably related to variability in imaging protocols and the qualifications of radiologists performing the procedure.

N Engl J Med 2008; 359: 1207-1217

Nasal insulin and diabetes prevention

Despite promising results in mouse models, prophylactic insulin administered to infants at risk of developing type 1 diabetes does not appear to prevent or delay the onset of the disease. Finnish researchers analysed the cord blood of over 100 000 babies to identify HLA susceptibility alleles for type 1 diabetes. In a double-blind trial, 224 infants and 40 of their siblings who tested positive for the antibodies were assigned to receive intranasal short-acting insulin or a placebo once a day. After a median of almost 2 years, there was no difference in the number of children diagnosed with diabetes in the treatment and placebo groups. The trial was terminated early due to the inability to show a beneficial effect of intranasal insulin in children with HLA-conferred susceptibility to type 1 diabetes.

Lancet 2008; 23 Sep [Epub ahead of print]

Dr Tanya Grassi, MJA

The Medical Journal of Australia eMJA