Obesity and cardiovascular disease. Aspects of methods and susceptibility

Sammanfattning: The aim of this thesis was to study the morbidity and mortality of cardiovascular disease (CVD) in obese individuals, as measured by different obesity measurements, and to explore how the CVD risk related to obesity was modified by other biologic and socio-demographic circumstances. Data from two population-based cohort studies was used. The Malmö Preventive Project included 22 444 middle-aged men, with a mean follow-up of 17.7 years. In a subcohort of 6193 men, information on inflammatory proteins was available. The Malmö Diet and Cancer Study included 28 098 men and women, with a mean follow-up of 7.6 years. National and local registers were used to follow the incidence of coronary events (CE), stroke and mortality. Body mass index (BMI) was an independent risk factor for CE and mortality in men. However, the risk associated with obesity was increased by exposure to other atherosclerotic risk factors (smoking, hypertension, diabetes mellitus and hyperlipidemia), of which smoking seemed to be the most important. Obesity was more prevalent in men with manual work and in men living alone, than in men with non-manual work and in cohabiting men. Adjusted for lifestyle and biological risk factors, the increased risk of CE and death for obese men with manual jobs was applicable only to those who were single. There was a positive interaction between obesity and living alone for incidence of CE. Increased BMI was related to plasma levels of inflammation-sensitive proteins (ISP) in men. The CVD risk varied widely between obese or overweight men with high and low ISP. Body fat percentage (BF%), measured by bioelectrical impedance method, was an independent risk factor for cardiovascular morbidity and mortality in men and women. BF% was a stronger CVD risk factor in women than in men. The raised CVD risk associated with high BF% was reduced by physical activity. Body fat distribution as measured by waist hip ratio (WHR) was associated with increased CVD risk. WHR added to the CVD risk in women at all levels of BMI and in men with normal weight. It is concluded that the susceptibility to CVD in obese people differs substantially according to subsets of other biologic and socio-demographic circumstances.