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Infertility & Sexual Dysfunction(구연)
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(E-186)
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Monthly variation in serum testosterone levels in middle-aged men |
| 을지병원 , 국립경찰병원¹, 성균관의대 삼성서울병원² |
| 이준호, 박연원¹, 조인창¹, 김병훈¹, 최재덕, 조정만, 강정윤, 유탁근, 이성원² |
<strong>Introduction</strong>: Testosterone has diurnal variation. However, it is unclear whether testosterone exhibits monthly variation. We conducted this study, to investigate whether we should consider or adjust for monthly variation in testosterone in the diagnosis of testosterone deficiency syndrome (TDS).
<strong>Methods</strong>: This was a prospective cross-sectional study. A total of 8,367 men were included. Total testosterone was measured between 7:00 and 9:00 AM. Additionally, data on age, waist circumference, blood pressure, fasting blood sugar, triglycerides, and high-density lipoprotein were collected and regarded as confounders. We also collected the monthly temperature and night time in Seoul. We, then, compared the ratio of testosterone <3.5 ng/mL and mean testosterone level of each month before and after adjusting confounders.
<strong>Results</strong>: Testosterone showed a monthly pattern with a nadir in May (4.4 ng/mL) and a peak in Jan (6.0 ng/mL). The relative difference ((peak – trough) / peak) was 24.9% and absolute difference (peak - trough) was 1.48 ng/mL. After adjusting confounders, testosterone also showed a monthly pattern with a nadir in May (4.514 ng/mL) and a peak in Jan (6.094 ng/mL). The ratio of <3.5 ng/mL also showed a monthly pattern with a nadir in Jan (2.7%) and a peak in May (24.1%). After adjusting, the odds ratio (OR) of testosterone<3.5ng/mL also showed a monthly pattern with a nadir in Jan (OR: 1.000) and a peak in May (OR: 11.445, 95% confidence interval: 6.288-20.832, P<0.001). A trendline of testosterone and night time duration of each month suggested positive relationship (Figure 1) between them.
<strong>Conclusions</strong>: Testosterone showed a monthly variation and this variation seems to be related to nighttime. In the diagnosis of TDS, this variation should be considered or adjusted.
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keywords : Monthly variation, Testosterone, Middle-aged men |
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