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Season of Conception, Smoking, and Preeclampsia in Norway

BACKGROUND: Preeclampsia (PE) is a dangerous and unpredictable pregnancy complication. A seasonal pattern of risk would suggest that there are potentially preventable environmental contributors, but prior analyses have not adjusted for confounding by PE risk factors that are associated with season o...

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Autores principales: Weinberg, Clarice R., Shi, Min, Basso, Olga, DeRoo, Lisa A., Harmon, Quaker, Wilcox, Allen J., Skjærven, Rolv
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Environmental Health Perspectives 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5743488/
https://www.ncbi.nlm.nih.gov/pubmed/28669933
http://dx.doi.org/10.1289/EHP963
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author Weinberg, Clarice R.
Shi, Min
Basso, Olga
DeRoo, Lisa A.
Harmon, Quaker
Wilcox, Allen J.
Skjærven, Rolv
author_facet Weinberg, Clarice R.
Shi, Min
Basso, Olga
DeRoo, Lisa A.
Harmon, Quaker
Wilcox, Allen J.
Skjærven, Rolv
author_sort Weinberg, Clarice R.
collection PubMed
description BACKGROUND: Preeclampsia (PE) is a dangerous and unpredictable pregnancy complication. A seasonal pattern of risk would suggest that there are potentially preventable environmental contributors, but prior analyses have not adjusted for confounding by PE risk factors that are associated with season of conception. METHODS: Seasonal effects were modeled and tested by representing each day of the year as an angle on a unit circle and using trigonometric functions of those angles in predictive models, using “harmonic analysis.” We applied harmonic Cox regression to model confounder-adjusted effects of the estimated day of the year of conception on risk of PE for births from the Medical Birth Registry of Norway for deliveries between 1999 and 2009. We also examined effect measure modification by parity, latitude (region), fetal sex, and smoking. RESULTS: In adjusted models, PE risk was related to season, with higher risk in spring conceptions and lower risk in autumn conceptions, with a risk amplitude (maximum compared with minimum) of about 20%. The pattern replicated across subpopulations defined by parity, latitude (region), fetal sex, and smoking. CONCLUSIONS: These results suggest that there is a seasonal driver for PE, with effects that are not modified by parity, latitude, fetal sex, or smoking. https://doi.org/10.1289/EHP963
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spelling pubmed-57434882017-12-31 Season of Conception, Smoking, and Preeclampsia in Norway Weinberg, Clarice R. Shi, Min Basso, Olga DeRoo, Lisa A. Harmon, Quaker Wilcox, Allen J. Skjærven, Rolv Environ Health Perspect Research BACKGROUND: Preeclampsia (PE) is a dangerous and unpredictable pregnancy complication. A seasonal pattern of risk would suggest that there are potentially preventable environmental contributors, but prior analyses have not adjusted for confounding by PE risk factors that are associated with season of conception. METHODS: Seasonal effects were modeled and tested by representing each day of the year as an angle on a unit circle and using trigonometric functions of those angles in predictive models, using “harmonic analysis.” We applied harmonic Cox regression to model confounder-adjusted effects of the estimated day of the year of conception on risk of PE for births from the Medical Birth Registry of Norway for deliveries between 1999 and 2009. We also examined effect measure modification by parity, latitude (region), fetal sex, and smoking. RESULTS: In adjusted models, PE risk was related to season, with higher risk in spring conceptions and lower risk in autumn conceptions, with a risk amplitude (maximum compared with minimum) of about 20%. The pattern replicated across subpopulations defined by parity, latitude (region), fetal sex, and smoking. CONCLUSIONS: These results suggest that there is a seasonal driver for PE, with effects that are not modified by parity, latitude, fetal sex, or smoking. https://doi.org/10.1289/EHP963 Environmental Health Perspectives 2017-06-29 /pmc/articles/PMC5743488/ /pubmed/28669933 http://dx.doi.org/10.1289/EHP963 Text en EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted.
spellingShingle Research
Weinberg, Clarice R.
Shi, Min
Basso, Olga
DeRoo, Lisa A.
Harmon, Quaker
Wilcox, Allen J.
Skjærven, Rolv
Season of Conception, Smoking, and Preeclampsia in Norway
title Season of Conception, Smoking, and Preeclampsia in Norway
title_full Season of Conception, Smoking, and Preeclampsia in Norway
title_fullStr Season of Conception, Smoking, and Preeclampsia in Norway
title_full_unstemmed Season of Conception, Smoking, and Preeclampsia in Norway
title_short Season of Conception, Smoking, and Preeclampsia in Norway
title_sort season of conception, smoking, and preeclampsia in norway
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5743488/
https://www.ncbi.nlm.nih.gov/pubmed/28669933
http://dx.doi.org/10.1289/EHP963
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