Long-term weight changes in obese young adult men and subsequent all-cause mortality.

BACKGROUND: Although the expectation is that weight gain increases mortality and weight loss among those overweight reduces mortality, results on weight gain and mortality in young adults are conflicting, and weight loss is less explored. We investigated the association between long-term weight change and all-cause mortality in a broad range of body mass index (BMI) in young men. METHODS: Among 362200 Danish draftees, examined between 1943 and 1977, all obese (BMI 31.0 kg m(-2); n=1930), and a random 1% sample of the others (n=3601) were identified at a mean age of 20 years (range: 18-25 years). All the obese and half the controls were re-examined between 4 and 40 years later (mean age 35 years). Weight changes were defined as: weight loss <-0.1 kg m(-2) per year, weight stability within ±0.1 kg m(-2) per year and weight gain >0.1 kg m(-2) per year. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression. RESULTS: Among the 908 obese and 1073 controls followed for 30 years after re-examination 220 and 232 died. HR of the weight stable obese was 2.32 (CI: 1.56-3.44) compared with the weight stable controls. In the obese cohort there was no association between weight loss, adjusted for initial BMI, and mortality (HR: 0.99; CI: 0.68-1.45) compared with weight stable obese. Too few controls lost weight to allow assessment of weight loss. Weight gain was associated with increased mortality in the obese (HR: 1.50; CI: 1.07-2.10) and controls (HR: 1.54; CI: 1.14-2.09) compared with weight stable obese and controls, respectively. Neither the time between the two examinations, life-style factors nor exclusion of diseased individuals influenced the results. CONCLUSIONS: Although there were increased mortality of the weight-stable obese compared with controls, there was no association between weight loss and mortality in the obese. Weight gain increased mortality regardless of the initial weight.

Body composition and body fat distribution in relation to later risk of acute myocardial infarction: a Danish follow-up study.

INTRODUCTION: Obesity is a modifiable risk factor for acute myocardial infarction (MI), but lean body mass (LBM) may also be an important factor. Low LBM may increase the risk of MI and LBM may modify the effect of obesity on MI. Thus, the inability of the classical anthropometric measures to evaluate LBM may lead to misclassification of MI risk in both lean and obese persons. We investigated the associations between incident MI and bioelectrical impedance analyses (BIA) derived measures of body composition in combination with body mass index (BMI) and anthropometric measures of body fat distribution. METHODS AND RESULTS: From 1993 to 1997, 27 148 men and 29 863 women, aged 50 to 64 year, were recruited into the Danish prospective study Diet, Cancer and Health. During 11.9 years of follow-up we identified 2028 cases of incident MI (1487 men and 541 women). BMI, waist circumference (WC), hip circumference and BIA of body composition including body fat mass (BFM), body fat percentage and LBM were measured at baseline. We used Cox proportional hazard models with age as time axis and performed extensive control for confounding. Weight, BMI, classical estimates of abdominal obesity and BIA estimates of obesity showed significant positive associations with incident MI. However, BFM adjusted for WC showed no association. Low LBM was associated with a higher risk of incident MI in both genders, and high LBM was associated with a higher risk in men. CONCLUSION: Obesity was positively associated with MI. Estimates of obesity achieved by BIA seemed not to add additional information to classical anthropometric measures regarding MI risk. Both high and low LBM may be positively associated with MI.

Weight change in later life and risk of death amongst the elderly: the European Prospective Investigation into Cancer and Nutrition-Elderly Network on Ageing and Health study.

OBJECTIVE: Later life weight change and mortality amongst elders. DESIGN: Nested case-control study. SETTING: Six countries from the European Investigation into Cancer and nutrition-Elderly, Network on Ageing and Health. SUBJECTS: A total of 1712 deceased (cases) and 4942 alive (controls) were selected from 34,239 participants, > or = 60 years at enrolment (1992-2000) who were followed-up until March 2007. Annual weight change was estimated as the weight difference from recruitment to the most distant from-date-of-death re-assessment, divided by the respective time. OUTCOME MEASURES: Mortality in relation to weight change was examined using conditional logistic regression. RESULTS: Weight loss > 1 kg year(-1) was associated with statistically significant increased death risk (OR = 1.65; 95% CI: 1.41-1.92) compared to minimal weight change (+/-1 kg year(-1)). Weight gain > 1 kg year(-1) was also associated with increased risk of death (OR = 1.15; 95% CI: 0.98-1.37), but this was evident and statistically significant only amongst overweight/obese (OR = 1.55; 95% CI: 1.17-2.05). In analyses by time interval since weight re-assessment, the association of mortality with weight loss was stronger for the interval proximal (< 1 year) to death (OR = 3.10; 95% CI: 2.03-4.72). The association of mortality with weight gain was stronger at the interval of more than 3 years and statistically significant only amongst overweight/obese (OR = 1.58; 95% CI: 1.07-2.33). Similar patterns were observed regarding death from circulatory diseases and cancer. CONCLUSIONS: In elderly, stable body weight is a predictor of lower subsequent mortality. Weight loss is associated with increased mortality, particularly short-term, probably reflecting underlying nosology. Weight gain, especially amongst overweight/obese elders, is also associated with increased mortality, particularly longer term.

Prenatal exposure to vitamin-D from fortified margarine and milk and body size at age 7 years.

BACKGROUND/OBJECTIVES: Prenatal vitamin-D deficiency may be associated with increased risk of obesity later in life. Using two national vitamin-D fortification programs as the setting for a societal experiment, we investigated whether exposure to vitamin-D from fortified margarine and low-fat milk during foetal life was associated with body size at 7 years of age. SUBJECTS/METHODS: Vitamin-D fortification of margarine was mandatory in Denmark from 1961 to 1985, and voluntary fortification of low-fat milk was permitted from 1972 to 1976. Using information on body mass index (BMI) Z-score at the age of 7 years of 54,270 children, who were measured during the mandatory Copenhagen School Health examination, we compared children according to whether the mothers were pregnant during the fortification programs or not. The comparisons were performed for children born just before and after initiation or termination of margarine and milk fortification periods, respectively. In total four sets of analyses were performed. RESULTS: We observed no difference in mean BMI Z-score between children exposed to vitamin-D fortification in utero and non-exposed children. Similar results were observed for overweight and obesity. CONCLUSIONS: Prenatal exposure to vitamin-D from fortification of margarine and low-fat milk showed no association with body size at 7 years.

Intake of ruminant trans fatty acids and changes in body weight and waist circumference.

BACKGROUND/OBJECTIVES: Follow-up studies have suggested that total intake of trans fatty acids (TFA) is a risk factor for gain in body weight and waist circumference (WC). However, in a cross-sectional study individual TFA isomers in adipose tissue had divergent associations with anthropometry. Our objective was to investigate the association between intake of TFA from ruminant dairy and meat products and subsequent changes in weight and WC. Furthermore, potential effect modification by sex, age, body mass index and WC at baseline was investigated. SUBJECTS/METHODS: Data on weight, WC, habitual diet and lifestyle were collected at baseline in a Danish cohort of 30,851 men and women aged 50-64 years. Follow-up information on weight and WC was collected 5 years after enrolment. The associations between intake of ruminant TFA (R-TFA) and changes in weight and WC were analysed using multiple linear regression with cubic spline modelling. RESULTS: Intake of R-TFA, both absolute and energy-adjusted intake, was significantly associated with weight change. Inverse associations were observed at lower intakes with a levelling-off at intakes >1.2 g/day and 0.4 energy percentage (E %). Absolute, but not energy-adjusted, intake of R-TFA was significantly associated with WC change. An inverse association was observed at lower intakes with a plateau above an intake of 1.2 g/day. CONCLUSIONS: The present study suggests that intake of R-TFA is weakly inversely associated with changes in weight, whereas no substantial association with changes in WC was found.