Publication date: 07 Jan 2022
What is already known about this subject:
- Cannabis is one of the most commonly consumed illicit drugs in Australia. Cannabis use during adolescence has been linked to poor physical health, difficulties in memory, poor academic performance and increased school dropout, mental health problems, lower life satisfaction and even suicide. Measures should therefore be taken to rigorously identify early-life presumptive risk factors of cannabis use in adolescence.
- The precise causes for cannabis use are multifactorial. Epidemiological studies hypothesize that the interactions between biological, psychological, social, and environmental factors may contribute to habitual use. Most importantly, a state of hardship or difficulty originating during fetal development such as low socioeconomic positions, parental substance use and mental health problems may increase the risk of mental health and behavioural problems in offspring later in life.
- There is a paucity of prospective longitudinal studies testing the associations between prenatal alcohol and tobacco exposures and the risk of cannabis use in offspring. Epidemiological evidence from the few available longitudinal studies shows that offspring exposed to prenatal tobacco may have an increased risk of illicit drug use compared to those non-exposed. However, to our knowledge, there is no study that has examined the link between prenatal alcohol and tobacco exposure and cannabis use in late adolescence. The aim of our study is to estimate the associations between prenatal alcohol and tobacco exposures (Gen1) and the risk of cannabis use in offspring (Gen2) at the age of 17 years. We hypothesized that such associations can be observed in offspring in late adolescence.
What this study adds
- Study participants were from the Raine Study. At 18 and 34 weeks of pregnancy, mothers reported an average of the total number of standard drinks of alcohol consumed per week and the number of cigarettes they had smoked per day during the first and third trimesters of pregnancy respectively
- We used these data to categorize pregnant mothers as either non-drinkers/non-smoker (non-exposed) or drinkers/ smoker (exposed). Cannabis use at 17 years of age (Gen2) was measured by using a self-reported questionnaire developed to capture risky behaviours in adolescents. Associations between prenatal alcohol and tobacco exposures and the risk of cannabis use in offspring were examined using log-binomial regression models, computing relative risks (RRs) as measure of association with STATA 16.1. We added different risk factors as adjustment variables in our models to better examine the role of potential confounders.
- The findings of this study suggest that offspring exposed to prenatal alcohol and tobacco use during the first and third trimesters were at increased risk of cannabis use at the age of 17 years when compared to unexposed offspring. Therefore, our findings need to be confirmed by other studies such as genetic sensitive studies that can elucidate specific causal pathways independent of social determinants. Nonetheless, based on the precautionary principle, this is additional evidence to support the recommendation that women should be encouraged to abstain from alcohol and tobacco during pregnancy.