Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort
Objective Season of birth has repeatedly been found to be a risk indicator for adverse neurodevelopmental outcomes. Several explanations for this finding have been put forward but no conclusion has been reached. In the current study, we explored the role of sociodemographic and biological factors in...
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BMJ Publishing Group
2017-02-01
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| Series: | BMJ Open |
| Online Access: | https://bmjopen.bmj.com/content/7/2/e012406.full |
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| author | Vincent W V Jaddoe Régine P M Steegers-Theunissen Henning Tiemeier Albert Hofman Frank C Verhulst Nina H Grootendorst-van Mil |
| author_facet | Vincent W V Jaddoe Régine P M Steegers-Theunissen Henning Tiemeier Albert Hofman Frank C Verhulst Nina H Grootendorst-van Mil |
| author_sort | Vincent W V Jaddoe |
| collection | DOAJ |
| description | Objective Season of birth has repeatedly been found to be a risk indicator for adverse neurodevelopmental outcomes. Several explanations for this finding have been put forward but no conclusion has been reached. In the current study, we explored the role of sociodemographic and biological factors in the association between season of birth and child IQ.Design In a prenatally recruited birth cohort (born in 2002–2006), we examined the association between season of birth and non-verbal IQ at age 6 years among 6034 children. We explored how adjusting for socioeconomic status and maternal IQ, childbirth outcomes, pregnancy vitamin D status, nutritional intake, exposure to infections, and child age relative to peers in class changed the relation between season of birth and child IQ.Results We found that spring birth was associated with lower non-verbal IQ (estimate: more than 1 point; β−1.24 (95% CI −2.31 to −0.17), p=0.02; seasonal trend β−0.40 (95% CI −0.74 to −0.07), p=0.02) than birth in summer. Adjustment for different covariates led to a substantial reduction (−65.0% change, in a seasonal trend analysis) of this association. In particular, sociodemographic factors and maternal IQ (−10.0% and −22.5% change, respectively) contributed.Conclusions Season of birth is an indicator of many underlying factors related to child IQ. The observed effects on IQ were small and therefore not of clinical significance. |
| format | Article |
| id | doaj-art-c676ca68226947a3acc94cca3f44f105 |
| institution | Kabale University |
| issn | 2044-6055 |
| language | English |
| publishDate | 2017-02-01 |
| publisher | BMJ Publishing Group |
| record_format | Article |
| series | BMJ Open |
| spelling | doaj-art-c676ca68226947a3acc94cca3f44f1052025-02-04T02:00:12ZengBMJ Publishing GroupBMJ Open2044-60552017-02-017210.1136/bmjopen-2016-012406Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohortVincent W V Jaddoe0Régine P M Steegers-Theunissen1Henning Tiemeier2Albert Hofman3Frank C Verhulst4Nina H Grootendorst-van Mil5Department of Paediatrics, Erasmus MC, Rotterdam, The Netherlands1 Department of Obstetrics and Gynecology, Erasmus MC, Rotterdam, The NetherlandsDepartment of Child and Adolescent Psychiatry, Erasmus Medical Center, Rotterdam, The Netherlands1Department of Epidemiology, Erasmus MC—University Medical Center Rotterdam, Rotterdam, The NetherlandsDepartment of Child and Adolescent Psychiatry and Psychology, Erasmus Medical Center, Rotterdam, The Netherlands1The Generation R Study Group, Erasmus MC, University Medical Center, Rotterdam, The NetherlandsObjective Season of birth has repeatedly been found to be a risk indicator for adverse neurodevelopmental outcomes. Several explanations for this finding have been put forward but no conclusion has been reached. In the current study, we explored the role of sociodemographic and biological factors in the association between season of birth and child IQ.Design In a prenatally recruited birth cohort (born in 2002–2006), we examined the association between season of birth and non-verbal IQ at age 6 years among 6034 children. We explored how adjusting for socioeconomic status and maternal IQ, childbirth outcomes, pregnancy vitamin D status, nutritional intake, exposure to infections, and child age relative to peers in class changed the relation between season of birth and child IQ.Results We found that spring birth was associated with lower non-verbal IQ (estimate: more than 1 point; β−1.24 (95% CI −2.31 to −0.17), p=0.02; seasonal trend β−0.40 (95% CI −0.74 to −0.07), p=0.02) than birth in summer. Adjustment for different covariates led to a substantial reduction (−65.0% change, in a seasonal trend analysis) of this association. In particular, sociodemographic factors and maternal IQ (−10.0% and −22.5% change, respectively) contributed.Conclusions Season of birth is an indicator of many underlying factors related to child IQ. The observed effects on IQ were small and therefore not of clinical significance.https://bmjopen.bmj.com/content/7/2/e012406.full |
| spellingShingle | Vincent W V Jaddoe Régine P M Steegers-Theunissen Henning Tiemeier Albert Hofman Frank C Verhulst Nina H Grootendorst-van Mil Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort BMJ Open |
| title | Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort |
| title_full | Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort |
| title_fullStr | Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort |
| title_full_unstemmed | Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort |
| title_short | Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort |
| title_sort | brighter children the association between seasonality of birth and child iq in a population based birth cohort |
| url | https://bmjopen.bmj.com/content/7/2/e012406.full |
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