Longitudinal associations of meteorological parameters during winter months in Sweden with self-reported symptoms of anxiety in the spring

Anxiety symptoms may be affected by environmental factors. Changes in weather patterns have been linked to various mental health outcomes, but research focusing on wintertime and anxiety is still sparse. Thus, we investigate longitudinal associations between solar radiation, precipitation, and snow days during winter-time and self-reported anxiety symptoms in the following spring. We used data from 14,237 participants of the Swedish Longitudinal Survey of Health who responded to surveys in spring 2016 and 2018. Symptoms of anxiety was assessed using SCL-ANX4, a subscale of the Symptom Checklist-25. Data on the daily solar radiation and precipitation was averaged over November to January and linked to the health data and residence at municipal level for each participant. For snow days, sum of days with snow over the 3-month period was used. Within-individual design using conditional logistic regression was used. Models were adjusted for age, region, and the remaining meteorological variables. Although odds ratios for anxiety in association with 3-month average solar radiation (OR 0.90, 95% CI 0.65-1.24) and precipitation (OR 0.91, 95% CI 0.79-1.05) were on the protective side, these associations were not statistically significant. We neither observed associations between snow days and anxiety symptoms, nor any significant effect modification by age, sex, civil status, job strain, occupational position, region, type of questionnaire, alcohol use, or physical activity (p-values for interactions > 0.05). Our findings do not demonstrate associations between wintertime weather conditions and symptoms of anxiety and call for further research from different geographical areas and populations.