Female sex and food insecurity in relation to self-reported poor or fair mental health in Canadian adults: a cross-sectional study using national survey data

BACKGROUND: Women with food insecurity are at higher risk for mental health disorders. This study examined the joint effect of female sex and food insecurity on self-reported poor or fair mental health in Canadian adults. METHODS: The analysis was based on data from adults (age ≥ 18 yr) who participated in the Canadian Community Health Survey (CCHS) 2015–2016. We determined past-year food security level (secure, moderately insecure or severely insecure) based on 18 questions. We used log-binomial regression to explore associations of sex and food insecurity with self-reported poor or fair mental health. We measured additive interaction between female sex and food insecurity using relative excess risk due to interaction (RERI). RESULTS: The overall response rate for the CCHS was 59.5%. Data for 61 446 respondents were analyzed. Poor or fair mental health was reported by 4107 participants (6.1% when weighted to the Canadian population). Increased risk of poor or fair mental health was associated with female sex (prevalence ratio [PR] 1.22, 95% confidence interval [CI] 1.12 to 1.31), and moderate (PR 2.50, 95% CI 2.21 to 2.82) and severe (PR 4.03, 95% CI 3.59 to 4.52) food insecurity. Significant additive interaction between female sex and severe food insecurity was found for those aged 40–64 years (RERI 1.38, 95% CI 0.29 to 2.47), and the PR for poor or fair mental health for severely food-insecure women was 5.55 (95% CI 4.48 to 6.89) compared to food-secure men of the same age group. INTERPRETATION: Poor or fair mental health is common in the food-insecure population, and there exists synergism between female sex and severe food insecurity among middle-aged people. This suggests the need to develop targeted mental health support strategies for food-insecure people, specifically middle-aged women.