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- Gaml-Sørensen, Anne, et al.
(författare)
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Maternal vitamin D levels and male reproductive health : a population-based follow-up study
- 2023
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Ingår i: European Journal of Epidemiology. - : Springer Science and Business Media LLC. - 0393-2990 .- 1573-7284. ; 38:5, s. 469-484
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Tidskriftsartikel (refereegranskat)abstract
- Maternal vitamin D levels during pregnancy may be important for reproductive health in male offspring by regulating cell proliferation and differentiation during development. We conducted a follow-up study of 827 young men from the Fetal Programming of Semen Quality (FEPOS) cohort, nested in the Danish National Birth Cohort to investigate if maternal vitamin D levels were associated with measures of reproductive health in adult sons. These included semen characteristics, testes volume, and reproductive hormone levels and were analysed according to maternal vitamin D (25(OH)D3) levels during pregnancy. In addition, an instrumental variable analysis using seasonality in sun exposure as an instrument for maternal vitamin D levels was conducted. We found that sons of mothers with vitamin D levels < 25 nmol/L had 11% (95% CI − 19 to − 2) lower testes volume and a 1.4 (95% CI 1.0 to 1.9) times higher risk of having low testes volume (< 15 mL), in addition to 20% (95% CI − 40 to 9) lower total sperm count and a 1.6 (95% CI 0.9 to 2.9) times higher risk of having a low total sperm count (< 39 million) compared with sons of mothers with vitamin D levels > 75 nmol/L. Continuous models, spline plots and an instrumental variable analysis supported these findings. Low maternal vitamin D levels were associated with lower testes volume and lower total sperm count with indications of dose-dependency. Maternal vitamin D level above 75 nmol/L during pregnancy may be beneficial for testes function in adult sons.
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2. |
- Gaml-Sørensen, Anne, et al.
(författare)
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The estimated effect of season and vitamin D in the first trimester on pubertal timing in girls and boys : A cohort study and an instrumental variable analysis
- 2023
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Ingår i: International Journal of Epidemiology. - 0300-5771. ; 52:5, s. 1328-1340
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Tidskriftsartikel (refereegranskat)abstract
- Background: Season of birth has been associated with age at menarche. Maternal vitamin D levels in pregnancy may explain this effect. We investigated whether the season of first trimester or maternal 25-hydroxyvitamin D3 [25(OH)D3] levels were associated with pubertal timing in children. Methods: We conducted a follow-up study of 15 819 children born in 2000-03 from the Puberty Cohort, nested in the Danish National Birth Cohort (DNBC). Mean differences in attaining numerous pubertal markers, including a combined estimate for the average age at attaining all pubertal markers, were estimated for low (November-April) relative to high (May-October) sunshine exposure season in the first trimester using multivariable interval-censored regression models. Moreover, we conducted a two-sample instrumental variable analysis using season as an instrument for maternal first-Trimester 25(OH)D3 plasma levels obtained from a non-overlapping subset (n = 827) in the DNBC. Results: For the combined estimate, girls and boys of mothers who had their first trimester during November-April had earlier pubertal timing than girls and boys of mothers whose first trimester occurred during May-October:-1.0 months (95% CI:-1.7 to-0.3) and-0.7 months (95% CI:-1.4 to-0.1), respectively. In the instrumental variable analysis, girls and boys also had earlier pubertal timing: respectively,-1.3 months (95% CI:-2.1 to-0.4) and-1.0 months (95% CI:-1.8 to-0.2) per SD (22 nmol/L) decrease in 25(OH)D3. Conclusions: Both first pregnancy trimester during November-April and lower 25(OH)D3 were associated with earlier pubertal timing in girls and boys.
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