Exploring the associations between number of children, multi-partner fertility and risk of obesity at midlife: Findings from the 1970 British Cohort Study (BCS70)

Sebastian Stannard; Ann Berrington; Nisreen A Alwan

doi:10.1371/journal.pone.0282795

Exploring the associations between number of children, multi-partner fertility and risk of obesity at midlife: Findings from the 1970 British Cohort Study (BCS70)

PLoS One. 2023 Apr 13;18(4):e0282795. doi: 10.1371/journal.pone.0282795. eCollection 2023.

Authors

Sebastian Stannard^{1

2

3}, Ann Berrington^{1

2}, Nisreen A Alwan^{3

4

5}

Affiliations

¹ Department of Social Statistics and Demography, University of Southampton, Southampton, United Kingdom.
² ESRC Centre for Population Change, University of Southampton, Southampton, United Kingdom.
³ Faculty of Medicine, School of Primary Care and Population Sciences, University of Southampton, Southampton, United Kingdom.
⁴ NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
⁵ NIHR Applied Research Collaboration Wessex, Southampton, United Kingdom.

Abstract

Background: Early parenthood, high parity, and partnership separation are associated with obesity. However, the emergence of non-marital partnerships, serial partnering and childbearing across unions, means that it is important to consider their association to obesity. This paper examined the associations between number of biological children and multi-partner fertility (MPF)-defined as having biological children with more than one partner, with obesity at midlife.

Method: The sample consisted of 2940 fathers and 3369 mothers in the 1970 British Cohort Study. The outcome was obesity (BMI 30 or over) at age 46. Fertility and partnership histories ascertained the number of live biological children and MPF status by age 42. The associations were tested using logistic regression adjusting for confounders at birth, age 10 and age 16. Adult factors recorded at age 42 including age at first birth, smoking status, alcohol dependency, educational attainment and housing tenure were considered as mediators.

Results: For fathers, obesity odds did not differ according to number of children or MPF. In unadjusted models, mothers with one child (OR 1.24 95%CI 1.01-1.51), mothers who had two children with two partners (OR 1.45 95%CI 1.05-1.99), and mothers who had three or more children with two or more partners (OR 1.51 95%CI 1.18-1.93) had higher odds of obesity. In adjusted models, there remained an association between mothers with one child and odds of obesity (OR 1.30 95%CI 1.05-1.60). All other associations were attenuated when confounders were included.

Conclusions: Mothers who had children with multiple partners had higher odds of obesity. However this association was completely attenuated when parental and child confounders were accounted for; suggesting that this association may be explained by confounding. Mothers who had one child only may be at increased odds of obesity, however this could be due to multiple factors including age at first birth.

Copyright: © 2023 Stannard et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Child
Cohort Studies
Female
Fertility
Humans
Infant, Newborn
Middle Aged
Mothers*
Obesity* / epidemiology
Pregnancy
Smoking

Grants and funding

This work was partly funded by the Economic and Social Research Council (UK) [ES/P000673/1]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.