Epidemiology
-
Net reclassification indices have recently become popular statistics for measuring the prediction increment of new biomarkers. We review the various types of net reclassification indices and their correct interpretations. We evaluate the advantages and disadvantages of quantifying the prediction increment with these indices. ⋯ When investigators want to test a null hypothesis of no prediction increment, the well-established tests for coefficients in the regression model are superior to the net reclassification index. If investigators want to use net reclassification indices, confidence intervals should be calculated using bootstrap methods rather than published variance formulas. The preferred single-number summary of the prediction increment is the improvement in net benefit.
-
Adherence to a Mediterranean diet has been associated with lower risk of various age-related diseases including dementia. Although narrative reviews have been published, no systematic review has synthesized studies on the association between Mediterranean diet adherence and cognitive function or dementia. ⋯ Published studies suggest that greater adherence to Mediterranean diet is associated with slower cognitive decline and lower risk of developing Alzheimer disease. Further studies would be useful to clarify the association with mild cognitive impairment and vascular dementia. Long-term randomized controlled trials promoting a Mediterranean diet may help establish whether improved adherence helps to prevent or delay the onset of Alzheimer disease and dementia.
-
Review Comparative Study
Risk factors and the sex differential in coronary artery disease.
In industrialized countries, the incidence of coronary artery disease is three to four times higher in men than in women. Our review examines whether differences in the prevalence of, or susceptibility to, various coronary risk factors might contribute to this sex differential. Cigarette smoking, hypertension, and hypercholesterolemia are risk factors for coronary artery disease in both sexes and are present at higher levels in middle-aged men than women. ⋯ In addition, men with a female pattern of abdominal fat distribution are at lower risk of coronary artery disease than those with a male pattern. In diabetic populations, the sex differential is greatly reduced, but studies on the effects of hyperinsulinemia and a lower insulin resistance in women compared with men are scarce. Prospective studies on the effect of fibrinogen and other hemostatic factors in women are also required.