Prevalence and risk of smoking behaviors following parental separation: a systematic review

Parental separation is a recognized adverse childhood experience that alters family structure and psychological development. While Western studies link family dissolution to substance use, synthesized prevalence and risk estimates, particularly within low- and middle-income countries like India, remain fragmented across different developmental stages. This systematic review evaluated the prevalence, odds, and moderating factors of smoking initiation, persistence, and nicotine dependence in offspring exposed to parental separation compared to those from intact families. Following the PRISMA guidelines, systematic searches were executed across PubMed/Medline, Embase, PsycInfo, Scopus, and Indian regional databases using the CoCoPop framework. Peer-reviewed observational studies evaluating childhood exposure to parental separation and subsequent smoking behaviors across global and Indian cohorts were included and assessed for risk of bias. A total of 22 observational studies met all inclusion criteria. Offspring exposed to parental separation demonstrated a consistently elevated risk of smoking initiation and regular tobacco consumption (odds ratio: 1.50-2.80$). Pooled smoking prevalence among individuals from separated households ranged from 28.5% to 52.0%, compared to 14.2% to 29.1% among peers from intact households. In India, exposure to parental marital disruption significantly predicted early tobacco experimentation, with bidis and smokeless tobacco accounting for a substantial proportion of initial use. Key moderating factors included post-separation socioeconomic decline, intergenerational parental smoking, male sex, and separation occurring in early childhood (<6 years). Main endpoints were smoking initiation, regular daily smoking, and nicotine reliance. Traditional tobacco (cigarettes and bidis) predominated; e-cigarette and pack-year data were unavailable, and no behavioral-disorder association was established. Parental separation serves as a robust, independent risk factor for early smoking onset and persistent nicotine reliance globally and within the Indian socio-cultural framework. Public health, school, and pediatric programs should routinely screen for family structural transitions to enable targeted prevention before tobacco habits become entrenched.