Epidemiology of obesity and its link to heart disease

Univariate analyses of many prospective studies have demonstrated that obesity increases the likelihood of developing cardiovascular disease. However, multivariate analyses have yielded more inconsistent results. Some studies have indicated that lean individuals have a greater total mortality than normal-weight individuals, but this may be attributable to the higher proportion of smokers in the lean population. Mexican Americans, a population with a high incidence of obesity, have the same mortality rate as non-Hispanic white Americans, suggesting that obesity does not increase their death rate. In the United States, the percentage of the population that is overweight has increased sharply since the 1970s, but the mortality rate has actually decreased. The increase in body weight has had little effect on mortality, possibly because factors associated with obesity, like hypertension, are treated more effectively. Large-scale clinical trials are required to determine the true effects of obesity on cardiovascular disease, diabetes and total mortality rate.