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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

Gaml-Sørensen, Anne ; Brix, Nis ; Ernst, Andreas ; Lunddorf, Lea Lykke Harrits ; Lindh, Christian LU orcid ; Toft, Gunnar ; Henriksen, Tine Brink ; Arah, Onyebuchi A. and Ramlau-Hansen, Cecilia Høst (2023) In International Journal of Epidemiology 52(5). p.1328-1340
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... (More)

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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author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
25-hydroxyvitamin D, delayed effects, fetal programming, instrumental variable analysis, maternal exposure, pregnancy season, prenatal exposure, pubertal development, Seasonal effect, vitamin D
in
International Journal of Epidemiology
volume
52
issue
5
pages
13 pages
publisher
Oxford University Press
external identifiers
  • scopus:85173559072
  • pmid:37178177
ISSN
0300-5771
DOI
10.1093/ije/dyad060
language
English
LU publication?
yes
id
6a0d9e42-7ddf-4cb1-a716-249f7be5ee5a
date added to LUP
2024-01-15 13:13:37
date last changed
2024-04-15 23:48:28
@article{6a0d9e42-7ddf-4cb1-a716-249f7be5ee5a,
  abstract     = {{<p>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.</p>}},
  author       = {{Gaml-Sørensen, Anne and Brix, Nis and Ernst, Andreas and Lunddorf, Lea Lykke Harrits and Lindh, Christian and Toft, Gunnar and Henriksen, Tine Brink and Arah, Onyebuchi A. and Ramlau-Hansen, Cecilia Høst}},
  issn         = {{0300-5771}},
  keywords     = {{25-hydroxyvitamin D; delayed effects; fetal programming; instrumental variable analysis; maternal exposure; pregnancy season; prenatal exposure; pubertal development; Seasonal effect; vitamin D}},
  language     = {{eng}},
  number       = {{5}},
  pages        = {{1328--1340}},
  publisher    = {{Oxford University Press}},
  series       = {{International Journal of Epidemiology}},
  title        = {{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}},
  url          = {{http://dx.doi.org/10.1093/ije/dyad060}},
  doi          = {{10.1093/ije/dyad060}},
  volume       = {{52}},
  year         = {{2023}},
}