Lifecourse relationship between maternal smoking during pregnancy, birth weight, contemporaneous anthropometric measurements and bone mass at 18 years old. The 1993 Pelotas Birth Cohort

Jeovany Martínez-Mesa,Ana Maria Baptista Menezes,Laura D Howe,Fernando Cesar Wehrmeister,Ludmila Correia Muniz,David Alejandro González-Chica,Maria Cecilia Assunção,Helen Gonçalves,Fernando C Barros

doi:10.1016/j.earlhumdev.2014.08.024

Abstract

BackgroundMaternal smoking during pregnancy is associated with short-term and also long-term harmful effects on offspring. ObjectiveThe aim of this study is to evaluate the associations of maternal smoking during pregnancy with offspring bone health at 18years old, and the role of birth weight and contemporaneous height, weight and body mass index (BMI) in this association.Data from the 1993 Pelotas Birth Cohort were analyzed using path analysis stratified by sex.Adolescents at 18years old (N=1512 males, 1563 females).DXA-determined total body bone mineral density (BMD) and bone mineral content (BMC) were assessed at 18years old. ResultsEach additional cigarette smoked during pregnancy was associated with a lower BMC by −4.20g in males (95% CI −8.37; −0.05), but not in females [−2.22g (95% CI −5.49; 1.04)]; weaker inverse associations were observed for BMD. This inverse association was explained by the influence of maternal smoking on birth weight and contemporaneous anthropometry, particularly height. A 1kg higher birth weight was associated with a higher BMC by around 144g in males and by around 186g in females, and also with a higher BMD by around 0.019g/cm2 in males and by around 0.018g/cm2 in females, respectively. ConclusionsLifecourse analysis using path models has enabled to evaluate the role of mediators in the associations of maternal smoking during pregnancy and birth weight with bone mass in the offspring, thus generating improved understanding of the etiology of bone health and the importance of early life experiences.

Highlights

Evidence has shown that smoking during pregnancy is harmful to the newborn [1,2,3,4], especially affecting birth weight [2,3,5]
In recent years there has been growing interest in the impact of early life events including smoking during pregnancy [6], and birth weight [7,8] on height during childhood and adolescence [9] and on bone health as an attempt at better understanding how these exposures contribute to the pathophysiology of osteoporosis [10,11]
Our findings point to an inverse association of maternal smoking during pregnancy with bone health

Summary

Introduction

Evidence has shown that smoking during pregnancy is harmful to the newborn [1,2,3,4], especially affecting birth weight [2,3,5]. Objective: The aim of this study is to evaluate the associations of maternal smoking during pregnancy with offspring bone health at 18 years old, and the role of birth weight and contemporaneous height, weight and body mass index (BMI) in this association. Results: Each additional cigarette smoked during pregnancy was associated with a lower BMC by −4.20 g in males (95% CI −8.37; −0.05), but not in females [−2.22 g (95% CI −5.49; 1.04)]; weaker inverse associations were observed for BMD This inverse association was explained by the influence of maternal smoking on birth weight and contemporaneous anthropometry, height. Conclusions: Lifecourse analysis using path models has enabled to evaluate the role of mediators in the associations of maternal smoking during pregnancy and birth weight with bone mass in the offspring, generating improved understanding of the etiology of bone health and the importance of early life experiences

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