Seasonal Variations in Sex Steroids in a Young Male Population and Their Relationship with Plasma Levels of Vitamin D

Abstract

Purpose Vitamin D (VD) acts on sperm motility, capacitation and survival but its role in steroidogenesis is less clear. Aims: To analyze seasonal variations in sex steroids and VD in a healthy male population. Materials and Methods Twenty-nine healthy males, 34.0±4.8 years were included. Blood collection in winter (W) and summer (S) was performed to measure: 25OHD, total testosterone (TT), free testosterone (FT), estradiol (E2), luteinizing hormone (LH), and sex hormone binding globulin (SHBG). Testosterone/estradiol (T/E2) ratio was calculated. Results In W, lower levels of 25OHD: 18.8±7.2 ng/mL vs . 38.8±11.9 ng/mL (p<0.0001) and LH: 3.5±1.2 mU/mL vs . 3.9±1.5 mU/mL (p=0.05), and higher levels of TT: 501.9±157.7 ng/dL vs . 405.0±128.0 ng/dL (p=0.0003), FT: 11.8±4.1 ng/dL vs . 10.2±3.7 ng/dL (p=0.017), SHBG: 28.5±10.9 nmol/L vs . 23.6±7.9 nmol/L (p=0.002) and T/E2 ratio: 30.7±19.7 ng/dL/pg/mL vs . 17.3±3.6 ng/dL/pg/mL (p=0.0015) with no variation in E2 levels were observed. A positive correlation between 25OHD and E2 (r=0.28, p=0.04) and negative correlations between 25OHD and TT (r=−0.27, p=0.049), 25OHD and FT (r=−0.32, p=0.01), and 25OHD and T/E2 (r=−0.44, p=0.0008) were found. Conclusions In healthy young male population, seasonal variations were observed in 25OHD and LH levels (higher in S) and in TT, FT, SHBG levels, and T/E2 (higher in W). Lower values of TT and FT in S are accompanied by higher levels of LH, which rules out a central mechanism for lowering testosterone. 25OHD negatively correlated with TT, FT, and T/E2 and positively correlated with E2, suggesting a relationship between VD status and changes in gonadal steroids.

Using LC-MS/MS to Determine Salivary Steroid Reference Intervals in a European Older Adult Population

“…Another important cycle to consider is the seasonality of hormones. Whilst the majority of evidence for the seasonality of hormones is from animal research [ 49 , 50 ], a growing number of studies have investigated this in humans, finding evidence for seasonal changes in dehydroepiandrosterone, cortisol, testosterone and estradiol [ 51 , 52 , 53 , 54 ]. Future work should investigate associations between seasonal changes in steroids and disease, with seasonal affective disorder and rheumatological conditions already being studied with regard to seasonal steroid variations [ 55 , 56 ].…”

Effects of Vitamin D Supplementation on Testosterone, Prostate, and Lower Urinary Tract Symptoms: A Prospective, Comparative Study

“…Furthermore, while most vitamin D supplementation studies conducted evaluations after a treatment period as short as 3 months to as long as 6 months, this study conducted vitamin D supplementation for one year. It has already been reported that seasonal differences in sunlight can affect vitamin D levels [ 28 30 ]. This study obtained data from only the age-matched control group who underwent health checkups at one-year intervals to minimize the effect of seasonal differences.…”

Association Between Atopic Dermatitis and Aging: Clinical Observations and Underlying Mechanisms

“…89 Furthermore, patients with AD often exhibit lower Vitamin D levels, which may be associated with hormonal fluctuations and reduced fertility. [90][91][92][93] A nationwide retrospective cohort study revealed that both mild and moderate-tosevere AD were significant risk factors for infertility. 94…”