Physical activity, sex steroid, and growth factor concentrations in pre- and post-menopausal women: a cross-sectional study within the EPIC cohort

PURPOSE

Increased physical activity (PA) is associated with a reduced risk of several cancers. PA may reduce cancer risk by changing endogenous hormones levels, but relatively little research has focused on this topic. The purpose of this study was to elucidate the relation between PA and endogenous hormone concentrations.

METHODS

A cross-sectional analysis of 798 pre- and 1,360 post-menopausal women included as controls in case-control studies on endogenous hormones (steroids, progesterone, sex-hormone-binding globulin (SHBG), and growth factors) levels, and cancer risk nested within European Prospective Investigation into Cancer and Nutrition cohort was performed. Multivariate regression analyses were performed to compare geometric mean levels of hormones and SHBG by categories of PA.

RESULTS

In pre-menopausal women, active women had 19 % significantly lower concentrations of androstenedione, 14 % lower testosterone, and 20 % lower free testosterone than inactive women, while no differences were observed for estrogens, progesterone, SHBG, and growth factors. In post-menopausal women, active women had 18 % significantly lower estradiol and 20 % lower free estradiol concentrations than inactive women, while no differences were observed for the other hormones and SHBG. More vigorous forms of physical activity were associated with higher insulin-like growth factor-I concentrations. Adjustment for body mass index did not alter the associations. Overall, the percentage of variance in hormone concentrations explained by PA levels was <2 %.

CONCLUSIONS

Our results support the hypothesis of an influence, although small in magnitude, of PA on sex hormone levels in blood, independent of body size.

Combined influence of leisure-time physical activity and hip circumference on all-cause mortality

Hip circumference has been shown to be inversely associated with mortality. Muscle atrophy in the gluteofemoral region may be a possible explanation and thus physical activity is likely to play an important role.

OBJECTIVE

To estimate the combined effects of hip circumference and physical activity on mortality.

DESIGN AND METHODS

From the Copenhagen City Heart Study, 3,358 men and 4,350 women aged 21 to 93 years without pre-existing diagnosis of diabetes, stroke, ischemic heart disease, or cancer in 1991-1994 and with complete information on the variables of interest were included in the analyses. The participants were followed to 2009 in the Danish Civil Registration System, with 1.3% loss to follow-up and 2,513 deaths. Hazard ratios (HR) were estimated for combinations of physical activity and hip circumference.

RESULTS

Hip circumference was inversely associated with mortality irrespective of being physically active or not. However, being physically active seemed to counterbalance some of the adverse health effects of a small hip circumference; when comparing inactive to active, the excess mortality at the 25th percentile of hip circumference is 40% in men (HR = 1.40, 95% CI: 1.14-1.72) and 33% in women (HR = 1.33, CI: 1.10-1.62). These associations were observed after adjustment for waist circumference and weight change in the 6 months before the examination.

CONCLUSION

Less effects of physical activity were found in individuals with greater hip circumferences. A small hip circumference appears hazardous to survival. However, being physically active may counterbalance some of the hazardous effects of a small hip circumference.