Department of Clinical Biochemistry, Black Country Pathology Services, Walsall Manor Hospital, Walsall, United Kingdom.
School of Medicine and Clinical Practice, Faculty of Science & Engineering, The University of Wolverhampton, Wolverhampton, United Kingdom.
Aging Male. 2024 Dec;27(1):2409189. doi: 10.1080/13685538.2024.2409189. Epub 2024 Oct 13.
Studies assessing variability of serum testosterone levels associated with seasonal environmental factors have been contradictory.
We assessed associations between the seasons and changes (δ) in seasonality indices and male serum total testosterone (δTT) variability.
Data were collected in 144 men with paired serum TT samples (126 non-fasting/18 fasting) analysed at Walsall Manor Hospital, UK (52.3 degrees North). Seasonal factors (ambient temperature within 15 min of sampling, humidity, precipitation, duration of daylight on the day of sampling, monthly average ambient temperature, and precipitation) were obtained from local weather-station archives. Sign-rank test determined inter-sample differences between TT and seasonality indices. Linear regression analyses studied associations between δTT and δ seasonal indices in the total cohort and subgroups (stratified by medians of age, TT and men with paired non-fasting samples). Sign-rank determined whether serum TT differed between the seasons.
Median inter-sample interval was 63 days. No significant inter-sample differences were evident regarding serum TT levels and seasonality indices. No associations were noted between δTT and δ seasonality indices in the total cohort and subgroups stratified by age and TT. Interestingly, δ ambient temperature ( = 0.012) and daylight duration ( = 0.032) were inversely associated with δTT in the 126 men in the non-fasting group (dependent variable). Only a small degree of the variability in the δTT was accounted by the above-mentioned independent variables. The seasons did not appear to influence serum TT values.
No relation was shown between seasonality and serum TT in the total cohort, thus possibly eliminating a confounding variable that could affect laboratory and clinical practice. It may be that seasonal variation in length of day is too modest at this latitude to demonstrate significant associations, hence our findings are latitude specific. We suggest that further data analysis to address this question in areas with greater seasonal variation would be appropriate.
评估与季节性环境因素相关的血清睾酮水平变异性的研究结果相互矛盾。
我们评估了季节与季节指数变化（δ）和男性血清总睾酮（δTT）变异性之间的关系。
数据来自英国沃尔索尔庄园医院（52.3 度北纬）的 144 名男性，他们的血清 TT 样本（126 份非禁食/18 份禁食）进行了配对分析。季节性因素（采样后 15 分钟内的环境温度、湿度、降水、采样当天的日照时间、每月平均环境温度和降水）从当地气象站档案中获得。符号秩检验确定了 TT 和季节指数之间的样本间差异。线性回归分析研究了总队列和亚组（按年龄、TT 和有配对非禁食样本的男性的中位数分层）中δTT 和δ季节指数之间的关联。符号秩检验确定了血清 TT 在不同季节之间是否存在差异。
中位数样本间间隔为 63 天。血清 TT 水平和季节指数之间没有明显的样本间差异。在总队列和按年龄和 TT 分层的亚组中，均未观察到δTT 与δ季节指数之间的关联。有趣的是，在非禁食组的 126 名男性中，δ环境温度（=0.012）和日光持续时间（=0.032）与δTT 呈负相关（因变量）。上述自变量仅能解释δTT 变异性的一小部分。季节似乎没有影响血清 TT 值。
在总队列中，季节与血清 TT 之间没有关系，因此可能消除了一个可能影响实验室和临床实践的混杂因素。可能是在这个纬度，白天长度的季节性变化太小，无法显示出显著的关联，因此我们的研究结果是特定于纬度的。我们建议，在季节性变化较大的地区，进一步分析数据以解决这个问题是合适的。
