OBJECTIVE: Obesity and underweight in young adulthood are associated with greater risk of future disability pension. Neither underlying causes of disability pension nor whether overweight confers excess risk is established in this age group. The aim of this study was to investigate risk of future disability pension according to body mass index (BMI) in young adulthood. DESIGN: BMI was measured at military conscription (1969-1994; n=1 191 027; mean age 18.3+/-0.5 years). Date and cause of disability pension, death and emigration dates were collected from national registers (1971-2006). Muscular strength, age, municipality, socioeconomic position, testing center and year were adjusted for in Cox regressions. RESULTS: During 28.4 million person-years, 60 024 subjects were granted disability pension. The hazard ratios (HRs) for underweight (1.14, CI 95% 1.11-1.17), overweight (1.36, 1.32-1.40), moderate (BMI 30-34.9; 1.87, 1.76 to 1.99) and morbid obesity (BMI>or=35; 3.04, 2.72-3.40) were elevated compared to normal weight. Not adjusting for muscular strength led to overestimation of the risk in underweight (1.27, 1.24-1.31), but underestimation in overweight (1.29, 1.25-1.33), moderately (1.72, 1.62-1.82) and morbidly obese subjects (2.77, 2.48-3.09). For circulatory and musculoskeletal causes, respectively, HRs were elevated only for overweight (2.06; 1.82-2.34; 1.47; 1.39-1.55) and obesity (3.51; 2.79-4.40; 2.15; 1.94-2.38). The same applied for tumors and nervous system, but not psychiatric causes, for which underweight (1.20; 1.16-1.24) displayed similar HR as overweight (1.21; 1.16-1.27), whereas the risk in obese subjects was higher (1.60; 1.46-1.75). CONCLUSION: The risks in overweight and obese, but not underweight, subjects were significantly elevated for each cause investigated. Although causality cannot be inferred, productivity losses associated with adverse BMI in young adulthood appear to be large.
BACKGROUND: An inverse association of IQ with mortality has been observed in previous studies. Analyses of associations between offspring's IQ and parental mortality in biological and non-biological family relations may shed light on genetic and environmental influences. METHODS: In a target cohort of 1,235,375 Swedish men, 931,825 (75%) men had complete data on all variables used. IQ of offspring was measured at age 18 and mothers and father were followed, on average, for 21.2 years and 19.7 years, respectively, with respect to all-cause and cause-specific mortality (cardiovascular disease, coronary heart disease, stroke and diabetes). The analyses were conducted by proportional hazards regression with adjustment for parental occupation, education and income. RESULTS: In adjusted analyses using IQ as a continuous variable over a standard nine-point scale, hazards ratio (HR) for all-cause mortality was 0.96 (95% CI 0.96 to 0.96) for fathers and 0.95 (0.95 to 0.95) for mothers. The corresponding HRs were 0.99 (0.97 to 1.00) for step-fathers and 0.97 (0.95 to 0.99) for step-mothers. In adjusted analyses, HRs for CVD mortality among fathers and mothers were 0.97 (0.96 to 0.97) and 0.94 (0.93 to 0.94) respectively. The corresponding HRs for diabetes mortality were 0.91 (0.89 to 0.92) among fathers and 0.85 (0.83 to 0.87) among mothers. CONCLUSIONS: The associations found in non-biological family relationships suggest shared environmental influences and/or assortative mating. Stronger IQ-mortality associations in biological than non-biological relationships suggest genetic influences. Stronger inverse offspring IQ-parental mortality associations in mothers than in fathers might be due to environmental factors or epigenetic mechanisms.
OBJECTIVE: To assess the size of biases in self-reported height, weight in a large sample of adolescents with special attention to possible effects of body dissatisfaction and to assess how such biases may influence estimates of overweight and obesity. DESIGN: Cross-sectional study. SETTING: Unselected population from Southwestern parts of Stockholm County, Sweden. SUBJECTS: Two-thousand seven hundred and twenty-six boys and girls, 15 years of age. METHODS: Data were collected by a questionnaire answered by adolescents and a physical examination made by trained study nurses. A validated physical appearance scale and body silhouettes were embedded into the questionnaire. RESULTS: Obese boys under-reported their weight (5.2 kg) (95% confidence intervals (CI) 3.7; 6.6) more than obese girls (3.8 kg) (95% CI 1.8; 5.8). Agreement between self-reported and measured body mass index (BMI)-categories (obese, overweight and non-overweight/obese) as estimated by weighted kappa was 0.77 (95% CI 0.72; 0.82) for girls and 0.74 (95% CI 0.70; 0.79) for boys. For obese girls and boys sensitivity of self-reports were 0.65 (95% CI 0.47; 0.79) and 0.52 (95% CI 0.38; 0.66). Boys with low scores on the physical appearance scale under-reported their weight and BMI more than those with high scores. Boys and girls who wished to be leaner under-reported their weight and BMI more than subjects who were satisfied with their body size (P
BACKGROUND AND OBJECTIVES: Body mass index (BMI) in adolescence may be of particular importance as a predictor of future risk of coronary heart disease (CHD). Associations measured either in childhood or in middle age have appeared to be weaker or non-existent. We investigated the association between BMI measured in adolescence and CHD, and also stroke, among middle aged Swedish men and controlled for potential confounders not included in previous studies. METHODS: Data on BMI, smoking and blood pressure (diastolic and systolic) was collected from 49,321 Swedish males, born during 1949-1951, at conscription for military service in 1969/70. Census data on socioeconomic indicators in childhood and adulthood was linked to the cohort. The men were followed from 1991 through 2004 in national registers with regard to mortality and hospitalization from CHD and stroke. RESULTS: A graded increase of CHD was seen in over six levels of BMI (BMI or =30, HR=4.3). A graded association between BMI and stroke was also found, although weaker. Adjustments for cardiovascular risk factors (smoking, diastolic and systolic blood pressure, and early cardiovascular mortality in parents) attenuated the relative risks to some extent, whereas adjustments for socioeconomic indicators in childhood and adulthood had minor effects. CONCLUSION: The results strongly suggest that BMI in late adolescence is an important predictor of both CHD and stroke among men before age 55 years, independent of smoking, hypertension and early cardiovascular mortality in parents.
BACKGROUND: Time trends in overweight, obesity and underweight among 10-year-old children were investigated between 1999 and 2003 with attention to gender and areas with different socioeconomic status (SES). MATERIAL: The study was performed in Stockholm County, where schools within eight different SES areas were randomly sampled. In selected schools, data on height and weight were abstracted from school health records of 2416 ten-year-old boys and girls examined by school nurses in 1999 and 2183 examined in 2003. RESULTS: Among boys, the prevalence of overweight was 21.6% in 1999 and 20.5% in 2003 (difference -1.1% (95% confidence interval (CI), -4.6; 2.4)) and for obesity 3.2 and 3.8% (difference 0.6% (95% CI, -0.9; 2.2)). Among girls overweight decreased from 22.1 to 19.2% (difference -2.9% (95% CI, -6.3; 0.6)) and obesity from 4.4 to 2.8% (difference -1.6% (95% CI, -3.1; 0.0)). There was a marginally significant difference in obesity trends in girls versus boys (P=0.051). The prevalence of underweight decreased nonsignificantly both in boys and in girls. Strong gradients, with more obesity and overweight in socioeconomically disadvantaged areas, were observed in both genders in 2003. Differences between SES areas were also seen in 1999 but were more pronounced in 2003. Among boys divergent trends in obesity were observed between 1999 and 2003, with evidence for increases in less affluent areas only. CONCLUSION: This population-based study of 10-year-olds indicates that rates of obesity, overweight and underweight are stable in Stockholm County. However, obesity is more prevalent in relatively less advantaged SES.
BACKGROUND: Inverse associations of birth length with suicide attempts have recently been reported. Whether growth during childhood alters this association is not known. The influences on patterns of growth in fetal life and childhood might be different for violent and non-violent suicide attempts. OBJECTIVE: To investigate the effect of fetal and childhood growth and possible effect modification on suicide attempts, both violent and non-violent, adjusting for potential maternal confounding factors. METHOD: 318 953 Men were followed by record linkage from the date of birth in Sweden (1973-1980) to the date of attempted suicide, date of death, emigration or to the end of 1999. RESULTS: The risk of suicide attempt was increased for men with reduced linear growth in fetal life across all levels of adult stature. Men with appropriate birth length for gestational age but short adult height also experienced a raised risk of suicide attempts: 1.56 (95% CI 1.2 to 2.1). Tall adult stature was protective. Short birth length for gestational age was more strongly related to violent (2.39; 95% CI 1.1 to 4.9) than non-violent (1.53; 95% CI 1.1 to 2.1) suicide attempts. The risk of violent attempts was most strongly increased for men with low birth weight and adequate adult stature: 2.54 (95% CI 1.1 to 5.7). CONCLUSIONS: The inverse association of linear growth in fetal life and suicide attempt does not seem to be modified by linear childhood growth. Short adult stature entails an additional risk. Short birth length seems particularly to increase the risk of violent suicide attempts.
OBJECTIVES: To investigate the contributions of genetic and environmental factors to the development of relative weight during the growth period. DESIGN: Longitudinal twin study. SUBJECTS: Two-hundred and thirty-one monozygotic and 144 dizygotic complete male twin pairs born between 1973 and 1979 were measured annually from birth to 18 years of age. RESULTS: Body mass index (BMI, kg/m(2)) at age 18 correlated with BMI at age 1 (r=0.32, 95% confidence intervals (CI) 0.21-0.42), and this correlation increased steadily up to age 17 (r=0.91, 95% CI 0.89-0.93). Major part (81-95%) of these trait correlations was attributable to correlate additive genetic factors, but also unique environmental correlations were present during the whole-growth period. The correlation between ponderal index (kg/m(3)) at birth and BMI at age 18 was small (r=0.09, 95% CI 0.02-0.15) and totally because of correlated unique environmental factors. CONCLUSIONS: Our results suggest persistent genetic regulation of BMI from age 1 to 18. However, environmental factors, not shared by siblings, also affected the correlations of BMI. A small specific environmental correlation was found between ponderal index at birth and BMI at age 18, which may reflect the effect of neonatal environmental factors on adult BMI. A challenge to the future research is to identify chromosome regions and specific genes regulating the development of BMI as well as environmental factors affecting BMI through the growth period independently or interacting with genetic factors.
OBJECTIVE: Measures of body size reflect genetic and environmental influences on growth and energy balance. Associations between such measures and risk of schizophrenia have been inconsistent. METHOD: This is a population-based cohort study of 1 347 520 men born in Sweden from 1952 to 1982, with height and body mass index (BMI) data available from conscription records. The Swedish National Hospital Discharge Register was used to identify subjects diagnosed with schizophrenia from 1970 to 2000. RESULTS: Subjects with lower BMI and shorter height had an increased risk of developing schizophrenia. Underweight subjects had an approximately 30% increase in risk compared with normal BMI subjects (adjusted HR = 1.30, 95% CI: 1.20-1.42). Tall subjects had an approximately 15% reduction in risk compared with short subjects (adjusted HR = 0.85, 95% CI: 0.80-0.92). CONCLUSION: Both height and BMI in early adulthood are strongly and inversely associated with risk of schizophrenia. We discuss these findings in relation to possible genetic and nutritional causal mechanisms.
BACKGROUND: While several studies have reported an inverse relation between IQ and total mortality rates, little is known about the association, if any, between IQ and disease-specific outcomes, particularly cancer. METHODS: A cohort of 959,540 Swedish men who underwent IQ testing at military conscription at around 19 years of age, and who were followed for incident cancer. Hazards ratios for the relation between IQ and 20 cancer outcomes were computed using Cox regression. RESULTS: During an average of 19.5 years of follow-up, there were 10 273 new cancer cases. IQ showed few associations with the cancer end points studied. There was a suggestion that IQ was positively associated with lung cancer, and inversely related to stomach, oesophageal and liver malignancies, although effects were modest. The only robust gradient was found for IQ in relation to skin cancer (HRper one standard deviation advantage in IQ; 95% confidence interval 1.18; 1.13, 1.24; P value for trend across categories:
OBJECTIVE: To assess whether the composition of the obese category (body mass index (BMI)> or =30) has changed during the last one-third of a century in young adult men. DESIGN: Retrospective study of 1,580,913 men (18.3+/-0.4 years) representing 82% of the Swedish male population at military conscription age between 1969 and 2005. Measured height and weight were used to define moderate and morbid obesity as BMI 30-34.9 and > or =35, respectively. Data on socio-economic position (SEP), place of residence (urban, semi-urban and rural), age and test center were also collected. RESULTS: From the period 1969-1974 to 2000-2005, the prevalence of moderate obesity almost quintupled (0.8-3.8%; P