Is Socioeconomic Position Related to the Prevalence of Metabolic Syndrome?: Influence of social class across the life course in a population-based study of older men

SHEENA E. RAMSAY PETER H. WHINCUP RICHARD MORRIS PHD LUCY LENNON MSC S.G. WANNAMETHEE PHD C a r d i o v a s c u l a r a n d Influence of social class across the life course in a population-based study of older men OBJECTIVE - To examine whether adult social class and childhood social class are related to metabolic syndrome in later life, independent of adult behavioral factors. RESEARCH DESIGN AND METHODS - This was a population-based cross-sectional study comprising 2,968 men aged 60 -79 years. RESULTS - Adult social class and childhood social class were both inversely related to metabolic syndrome. Mutual adjustment attenuated the relation of metabolic syndrome with childhood social class; that with adult social class was little affected. However, the relation with adult social class was markedly attenuated by adjustment for smoking status, physical activity, and alcohol consumption. High waist circumference was independently associated with adult social class. CONCLUSIONS - The association between adult social class and metabolic syndrome was largely explained by behavioral factors. In addition, central adiposity, a component of metabolic syndrome, was associated with adult social class. Focusing on healthier behaviors and obesity, rather than specific efforts to reduce social inequalities surrounding metabolic syndrome, is likely to be particularly important in reducing social inequalities that affect people with coronary disease. - T the relationship between socioecohere has been increasing interest in nomic position and metabolic syndrome, which is postulated to form a direct pathway linking adverse social conditions and coronary heart disease (CHD), possibly working through neuroendocrine mechanisms causing obesity, dyslipidemia, hypertension, and insulin resistance (1,2). However, the association between socioeconomic position and metabolic syndrome has not been completely consistent between studies (1,3,4), and the relationship is possibly confounded by behavioral factors, which are strongly related to metabolic syndrome, and to socioeconomic position (3 6). Additionally, few studies have explored the independent relationships of adult and early-life social circumstances with metabolic syndrome (4,7,8). We have, therefore, examined whether adult and childhood social class may be associated with metabolic syndrome in older men (aged 60 79 years) independently of adult behavioral factors. RESEARCH DESIGN AND METHODS The British Regional Heart Study comprises a populationbased cohort of men recruited in 1978 1780 at age 40 59 years from 24 British towns (5). In 1998 2000, all surviving subjects, now aged 60 79 years, were invited to attend a physical examination and provide fasting blood samples used to measure metabolic parameters (5). Of these men, 4,252 (77%) attended the examination and 4,094 (74%) provided at least one measurement of biological factors. Adult socioeconomic position was measured as social class based on the longest-held occupation recorded at study entry (aged 40 59 years), using the Registrar Generals classification: I (professional, e.g., physicians, engineers), II (managerial, e.g., teachers, sales managers), III-nonmanual (semi-skilled nonmanual, e.g., clerks, shop assistants), IIImanual (semi-skilled manual, e.g., bricklayers), IV (partly skilled, e.g., postmen), and V (unskilled, e.g., porters, laborers). Childhood social class, based on the fathers longest-held occupation collected through questionnaires in 1992, was organized with the Registrar Generals classification of 1931 (which approximates the study participants midyear of birth) into six social classes from I to V (9). Questionnaires in 1998 2000 collected information on cigarette smoking, alcohol intake, and physical activity (5). Metabolic syndrome, defined using National Cholesterol Education Programme/ Adult Treatment Panel III criteria, required participants to meet at least three of the following requirements: 1) fasting plasma glucose 110 mg/dl, 2) serum triglycerides 150 mg/dl, 3) serum HDL cholesterol 40 mg/dl, 4) blood pressure 130/85 mmHg or antihypertensive treatment, and 5) waist circumference 102 cm (10). Insulin resistance was estimated, using homeostasis model assessment, as the product of fasting glucose and insulin divided by the constant 22.5 (11). Men with prevalent diabetes (doctordiagnosed diabetes or fasting glucose 7 mmol/l; n 385) and men whose own (n 112) or whose fathers (n 81) occupation was in the armed forces were excluded from the analysis. Multiple lo1.00 1.08 (0.801.48) 1.24 (0.861.79) 1.47 (1.101.98) 1.37 (0.941.99) 1.64 (0.982.76) 0.0005 1.00 1.06 (0.781.45) 1.19 (0.821.73) 1.38 (1.021.88) 1.26 (0.861.86) 1.50 (0.882.54) 0.008 Ramsay and Associates 1.33 (1.131.57) 1.27 (1.071.50) 1.21 (1.021.43) 1.24 (1.041.49) 1.13 (0.931.37) 1.17 (0.971.41) Data are n (%) or OR (95% CI) unless otherwise indicated. *Adult and childhood (...truncated)