Tobacco smoking and oestrogen replacement are associated with lower total and central fat in monozygotic twins

Abstract

BACKGROUND: The known postmenopausal increase in cardiovascular risk may relate in part to changes in fat distribution. Environmental factors which are known to in¯uence cardiovascular disease risk may do so in part by in¯uencing body fat and its distribution. OBJECTIVES: To determine the relationships between tobacco smoking, oestrogen replacement (ERT) and body fat and its distribution in postmenopausal women, independent of genetic factors, physical activity, diet composition and socioeconomic factors. DESIGN: Cross-sectional study in normal post menopausal twins. SUBJECTS: 712 postmenopausal female twins (aged 58.7 AE 0.2 y, body mass index (BMI) 24.4 AE 0.1 kgam 2 ). MEASUREMENTS: Anthropometry; body composition and fat distribution by dual energy x-ray absorptiometry; physical activity, muscle strength, socioeconomic status, dietary composition and dehydroepiandrosterone sulfate (DHEAS). RESULTS: In monozygotic pairs discordant for smoking, intrapair differences in total and central fat were greater than that in concordant pairs, with the lower fat mass in the smoking twin. Overall, smokers had a lower weight, BMI, total and central abdominal fat, despite a higher total and saturated dietary fat intake and similar DHEAS levels. The reduction in central fat was not independent of that in total fat. In monozygotic twins discordant for ERT-use the intrapair differences in total and central body fat were signi®cantly greater than in concordant pairs, with the lower fat measure in the ERT-using twin. Overall, current ERT-users had similar body weight, BMI and total fat compared to non-users but had lower central fat. There were no differences in activity levels, diet or socioeconomic factors between ERT-users and non-users. CONCLUSIONS: Smoking and ERT-use are associated with lower total and central fat in monozygotic postmenopausal twins. In current smokers, the lower central adiposity appears related to its in¯uence on total body fat. In ERT-users, lower central fat may contribute to the reduced cardiovascular risk associated with postmenopausal oestrogen use.

Relationships of age, menopause and central obesity on cardiovascular disease risk factors in Chinese women

“…Several studies have also proved that hormone replacement therapy can prevent the increment of total body fat and abdominal fat that occurs after estrogen depletion during menopause. 24,30 These results seemed to support the unique and important effect of menopause on changes in body composition. 6 On the other hand, through the aging process, the fat-free mass will be decreased and the body composition will encompass more fat tissue mass with the tendency of central accumulation.…”

“…11 Meanwhile, the fact that hormone replacement therapy can prevent central distribution of body fat indicates the important role of the sex hormone. 24,30 Furthermore, normal menopause is associated with reduced energy expenditure (REE). 5 The variation of REE was further signi®cantly associated with the difference of trunk lean and fat tissue mass.…”

Association of visceral fat with coronary risk factors in a population-based sample of postmenopausal women

“…These results are in agreement with the finding that female smokers had decreased abdominal obesity evaluated by waist circumference and densitometry. 34 Since only one woman smoked more than 20 cigarettes per day, statistical differences in VAT values may perhaps be found in groups with an increased amount of cigarettes smoked per day.…”

The non-genetic determinants of central adiposity*

“…In our study of British postmenopausal twins, current smoking was associated with lower total body fat and lower central abdominal fat, using both waist circumference and direct measures. 71 Importantly, in identical twin pairs where only one twin smoked, when factors such as genes, age, menopausal status and HRT were controlled for, the smoking twin had lower central fat. 71 If smoking does not increase central fat, how does it exert its effects on insulin resistance and cardiovascular risk?…”