Ambient environmental exposures and mental health outcomes in Mozambique: a population-based nationally representative survey

BackgroundAlthough the impact of climate change on mental health is widely acknowledged, there is a critical lack of empirical evidence from sub-Saharan Africa. We used a nationally representative cross-sectional study conducted in Mozambique to assess whether ambient environmental exposures are associated with symptoms of anxiety or depression. MethodsMental health data from the 2022-2023 Mozambique Demographic and Health Survey were linked to remotely sensed climate and environmental variables, and associations were determined using the modified Poisson regression. ResultsA total of 13,138 women and 5,380 men were included in the study. The prevalence of anxiety was 11.1% among women and 2.1% among men, whilst depressive symptoms were 10.1% in women and 2.3% in men. Among women, higher mean daily temperatures (>24.6{degrees}C) were associated with an increased likelihood of symptoms of anxiety (adjusted risk ratio [aRR] = 2.89, 95% CI: 2.13-3.95; p < 0.0001) and depression (aRR = 3.45, 95% CI: 2.46-4.84; p < 0.0001). High annual precipitation (>1201mm) was associated with a >2-fold higher likelihood of either outcome, while relative humidity (68.4%-74.2%) was associated with a >2-fold higher likelihood of either outcome. In contrast, high environmental greenness (NDVI >0.56) was associated with at least a 49% decrease in symptoms of either outcome. No clear associations were observed among men. ImplicationsExposure to high temperatures, humidity, and precipitation was associated with an increased risk of adverse mental health outcomes among women in Mozambique. These findings underscore the need for targeted policy responses, including the development of green spaces and enhanced flood mitigation, to promote resilience and safeguard mental health among vulnerable populations. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSThere is limited evidence from sub-Saharan Africa on the mental health impacts of climate-related exposures such as temperature, humidity, precipitation, and vegetation cover. Most existing studies are from high-income or Asian settings, with few studies examining gender or age-specific vulnerabilities. Literature suggests that women may be disproportionately affected by climate stressors due to biological, social, and economic factors, though evidence from sub-Saharan Africa remains scarce. Age differences in climate-related mental health impacts are also understudied. Added value of this studyTo our knowledge, this is one of the first studies from Mozambique, and more broadly from Africa, to examine associations between climate factors and mental health outcomes. We found that higher temperatures, relative humidity, and precipitation were associated with a greater likelihood of depression, anxiety, and their co-occurrence. In contrast, higher environmental greenness was protective across these outcomes. Importantly, these associations were observed among women but not among men, highlighting a potential gender differential in vulnerability to environmental exposures. Implications of all the available evidenceOur findings emphasize the urgent need to expand research on climate and mental health in African contexts, with attention to gender and age differences. The apparent greater vulnerability of women suggests that climate-related mental health impacts may exacerbate existing gender inequities. Interventions aimed at climate adaptation--including expanding green spaces and flood mitigation--could help protect mental health, particularly for women in similar settings.