Association between maternal smoking during pregnancy and risk of bone fractures in offspring: a systematic review and meta-analysis

Abstract

This study aimed to investigate the effect of maternal smoking during pregnancy (MSDP) on the risk of bone fractures in the offspring through a systematic review and meta-analysis. The PubMed, Web of Science, and Scopus databases were systematically searched for relevant articles published through July 2019. According to heterogeneity, the pooled risk ratio (RR) and odds ratio (OR) and their corresponding 95% confidence interval (CI) were obtained using fixed or random effects models. The heterogeneity and quality of the included studies were assessed by the I-squared (I 2) statistic and the Newcastle-Ottawa scale, respectively. Sensitivity analyses were performed to test the effect of MSDP misclassification on the results. The review of 842 search records yielded 5 studies including 8,746 mother-child pairs that were included in the meta-analysis. Pooling adjusted effect measures showed that MSDP was not associated with a later risk of bone fractures in the offspring (pooled RR, 1.15; 95% CI, 0.84-1.58; I 2 =66.8%; P=0.049). After the adjustment for misclassification, MSDP may be associated with a 27% increased risk of bone fracture (pooled OR, 1.27; 95% CI, 1.00-1.62; I 2 =0%; P=0.537). After the adjustment for misclassification, MSDP is associated with an increased risk of bone fractures among children whose mothers smoked during pregnancy.

Prevalence of vitamin D deficiency in children presenting with supracondylar fractures of humerus

“…13,14 Adequate intake of vitamin D in infants and pregnant women also plays a significant role in bone mineralisation. 15 Several studies have results like our study, however, many studies are against our conclusion. Sheth et al in their study concluded that children with fractures have lower levels of serum calcium and phosphorus.…”

“…Vitamin D deficiency is more prevalent in areas with poor socio‐economic status because of unmet demands of milk and dairy products among children 13,14 . Adequate intake of vitamin D in infants and pregnant women also plays a significant role in bone mineralisation 15 …”

Effect of parental supervision of infants at age 4 to 6 months on injuries at age 4 to 12 months

“…The role of parents in assuring the safety and reducing the risk of injury in their children depends on the age and development stage of the children, the occupation and socioeconomic status of the parents, and the specific cultural environment 8 . The risk of child injury is influenced by parental awareness, attitudes, and behaviors related to the safety of their children 8 – 10 . A meta-analysis reported that increased education or intervention by parents effectively prevented childhood injuries and improved safety at the home 11 .…”

Is correcting exposure misclassification bias an additional option in meta-analyses?

“…Meta-analyses require a systematic review of many studies; to reduce errors, the research is conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement [ 2 ] or MOOSE (Meta-analysis Of Observational Studies in Epidemiology) standards [ 1 ]. Ayubi et al [ 2 ] illustrated this process using a 27-item checklist and suggested a statistical method for correcting misclassification bias in the appendix to make it reproducible.…”

“…They synthesized 2 sets of analyses of the association between a misclassified exposure and an outcome (main studies) and the association between misclassified exposure and true exposure (validation studies) by using the extended Bayesian approach. Ayubi et al [ 2 ] solved the errors based on the fact that smoke exposure was determined by the mother’s recall at the age of 8 or 9 years, indicating that the smoker group could be classified as a nonsmoker group, and drew meaningful results by using Bayesian analysis to correct for misclassification bias that may occur in a meta-analysis of the effects of exposure.…”