Schliep Karen C, Schisterman Enrique F, Wactawski-Wende Jean, Perkins Neil J, Radin Rose G, Zarek Shvetha M, Mitchell Emily M, Sjaarda Lindsey A, Mumford Sunni L
Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, MD; Department of Family and Preventive Medicine, University of Utah Health Sciences Center, Salt Lake City, UT;
Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, MD;
Am J Clin Nutr. 2016 Jul;104(1):155-63. doi: 10.3945/ajcn.115.118430. Epub 2016 May 25.
Clinicians often recommend limiting caffeine intake while attempting to conceive; however, few studies have evaluated the associations between caffeine exposure and menstrual cycle function, and we are aware of no previous studies assessing biological dose via well-timed serum measurements.
We assessed the relation between caffeine and its metabolites and reproductive hormones in a healthy premenopausal cohort and evaluated potential effect modification by race.
Participants (n = 259) were followed for ≤2 menstrual cycles and provided fasting blood specimens ≤8 times/cycle. Linear mixed models were used to estimate associations between serum caffeine biomarkers and geometric mean reproductive hormones, whereas Poisson regression was used to assess risk of sporadic anovulation.
The highest compared with the lowest serum caffeine tertile was associated with lower total testosterone [27.9 ng/dL (95% CI: 26.7, 29.0 ng/dL) compared with 29.1 ng/dL (95% CI: 27.9, 30.3 ng/dL), respectively] and free testosterone [0.178 ng/mL (95% CI: 0.171, 0.185 ng/dL) compared with 0.186 ng/mL (95% CI: 0.179, 0.194 ng/dL), respectively] after adjustment for age, race, percentage of body fat, daily vigorous exercise, perceived stress, depression, dietary factors, and alcohol intake. The highest tertiles compared with the lowest tertiles of caffeine and paraxanthine were also associated with reduced risk of anovulation [adjusted RRs (aRRs): 0.39 (95% CI: 0.18, 0.87) and 0.40 (95% CI: 0.18, 0.87), respectively]. Additional adjustment for self-reported coffee intake did not alter the reproductive hormone findings and only slightly attenuated the results for serum caffeine and paraxanthine and anovulation. Although reductions in the concentrations of total testosterone and free testosterone and decreased risk of anovulation were greatest in Asian women, there was no indication of effect modification by race.
Caffeine intake, irrespective of the beverage source, may be associated with reduced testosterone and improved menstrual cycle function in healthy premenopausal women.
临床医生在建议备孕女性尝试受孕时，通常会建议限制咖啡因摄入量；然而，很少有研究评估咖啡因暴露与月经周期功能之间的关联，而且我们所知，之前尚无通过适时的血清测量来评估生物剂量的研究。
我们评估了健康绝经前队列中咖啡因及其代谢物与生殖激素之间的关系，并评估了种族对潜在效应的修饰作用。
对259名参与者进行了≤2个月经周期的随访，每个周期采集≤8次空腹血标本。采用线性混合模型估计血清咖啡因生物标志物与几何平均生殖激素之间的关联，采用泊松回归评估偶发性无排卵的风险。
在对年龄、种族、体脂百分比、每日剧烈运动、感知压力、抑郁、饮食因素和酒精摄入量进行调整后，血清咖啡因三分位数最高组与最低组相比，总睾酮水平较低[分别为27.9 ng/dL（95%置信区间：26.7，29.0 ng/dL）和29.1 ng/dL（95%置信区间：27.9，30.3 ng/dL）]，游离睾酮水平也较低[分别为0.178 ng/mL（95%置信区间：0.171，0.185 ng/dL）和0.186 ng/mL（95%置信区间：0.179，0.194 ng/dL）]。咖啡因和副黄嘌呤三分位数最高组与最低组相比，无排卵风险也降低[校正风险比（aRRs）分别为：0.39（95%置信区间：0.18，0.87）和0.40（95%置信区间：0.18，0.87）]。对自我报告的咖啡摄入量进行额外调整并没有改变生殖激素的研究结果，只是略微减弱了血清咖啡因和副黄嘌呤与无排卵之间的关联结果。虽然亚洲女性总睾酮和游离睾酮浓度的降低以及无排卵风险的降低最为明显，但没有迹象表明种族对效应有修饰作用。
在健康的绝经前女性中，无论饮料来源如何，咖啡因摄入量可能与睾酮水平降低和月经周期功能改善有关。
