Aging
Does healthy behaviour make you look good? Zhu Liduzi Jiesisibieke* Zhu Liduzi Jiesisibieke Zhu Liduzi Jiesisibieke C Mary
Background: Motivations to improve health may vary; improving personal attractiveness could be a powerful motivator. We investigated whether health-related behaviours commonly mentioned by the World Health Organization also affected appearance (facial aging) in men or women using Mendelian randomization.
Methods: We identified independent (r2<0.001) genetic variants strongly (p<5e-8) predicting body mass index, smoking, alcohol use, diet (omega-3, omega-6) and to allow for differences by sex testosterone and estrogen; we then considered their impact on facial aging. We used inverse variance weighted estimates with sensitivity analysis and assessed sex differences using a z-test.
Results: Body mass index (per standard deviation (SD)) was positively associated with facial aging in both men (beta 0.07, 95% confidence intervals (CI) 0.05 to 0.08) and women (0.04, 95% CI 0.02 to 0.05) (p value for sex-difference 0.002). Smoking status (cigarettes per day) was also associated with facial aging (beta 0.02, 0.01 to 0.04, p value for sex-difference 0.89), but not smoking initiation with little evidence of a sex difference. Alcohol use was unrelated to facial aging. In men, omega-3 (per SD), but not omega-6, was positively associated with facial aging (beta 0.02, 95% CI 0 to 0.03), but less clearly in women (p value for sex-difference 0.20). Among men, testosterone was associated with facial aging (beta 0.03 per SD, 0.01 to 0.04), while no such association was found in women (p value for sex-difference 0.02). In women, estrogen (pmol/L) protected against facial aging (beta -0.01, -0.03 to -0.001), although this was not evident in men (p value for sex-difference 0.41).
Conclusions: Adiposity, smoking, omega-3 fatty acids and testosterone may adversely affect appearance, but estrogen may enhance appearance. Whether these insights could be utilized as additional motivators for healthy behaviour, such as weight loss and smoking cessation, could be investigated.