Adult obesity and number of yearS lived with and without cardiovascular disease

Nutrition Research Newsletter, Oct, 2006

The prevalence of overweight has increased continuously over the last 20 years. It has been shown that being overweight is associated with risk factors for cardiovascular disease (CVD) such as hypertension, hypercholesterolemia, and diabetes and the risk of CVD itself. However, to provide comprehensive information for public and individual health care planning, it is necessary to move from measures such as relative risk to measures of the lifetime consequences of excess weight. While it is known that overweight increases the risk of CVD, it is unknown whether overweight people would live fewer or more years with CVD compared with those of normal weight. The objective of this study was to determine the differences in the average number of years lived free of CVD (that is, before the onset of CVD or death) and the average number of years lived with CVD for subjects who were normal weight, pre-obese, or obese at 45 years of age.

The researchers constructed multistate life tables for CVD, myocardial infarction, and stroke, using data from 2551 enrollees (1130 men) in the Framingham Heart Study who were 45 years of age. Obesity and pre-obesity were associated with fewer number of years free of CVD, myocardial infarction, and stroke and an increase in the number of years lived with these diseases. Forty-five-year-old obese men with no CVD survived 6 years fewer than their normal weight counterparts, whereas, for women, the difference between obese and normal weight subjects was 8.4 years. Obese men and women lived with CVD 2.7 years and 1.4 years longer, respectively, than normal weight individuals.

Number of years lived free of CVD is a composite health measure resulting from a combination of two major effects: incidence of CVD and mortality in those without previous cardiovascular disease. In this analysis, the increased risk of incident disease for obese and pre-obese subjects compared with their normal weight counterparts was reflected in an earlier occurrence of disease and a higher proportion of cases throughout life. Additionally, the increased risk of mortality in those without previous CVD resulted in a decreased number of years lived and, consequently, an even shorter number of years lived free of CVD. The finding that obesity was associated with a greater number of years lived with CVD suggests that differences in number of years lived with CVD were driven largely by the increased risk of incident disease associated with obesity, exceeding the effect of the higher relative risks of mortality.

The obesity epidemic continues, despite substantial research in the area. While a range of strategies, from social policy to patient care, is required to halt this epidemic, accurate and meaningful measures of risk are required to underpin all strategies. It is known that different methods of communicating risk result in different perceptions of risk. Here the researchers present a relatively new method of risk presentation: that of number of years lived with and without CVD. For risk factors such as obesity, whose downstream effects are multiple and extend into old age, it will be increasingly important to understand their effects across the life course, presenting both the time to disease and the time lived with disease. These findings constitute a solid basis for well-informed public and clinical prioritization of obesity prevention.

C. Pardo Silva, C. De Laet, W. Nusselder, et al. Adult Obesity and Number of Years Lived with and without Cardiovascular Disease. Obes Res; 14; 1264-1273 (July 2006) [Correspondence: Anna Peeters. Department of Epidemiology and Preventive Medicine, Monash University Central and Eastern Clinical School, Alfred Hospital Commercial Road, Melbourne, Victoria 3004, Australia. E-mail: anna.peeters@med.monash.edu.au]