Time series analysis of suicide from a monthly perspective in the south of Brazil: an ecological study

Introduction: Suicide is the cause of death of almost 800 thousand people worldwide every year. In Brazil, Rio Grande do Sul is one of the states with the highest suicide rates. This study aimed to assess whether there is a significant monthly time pattern of suicide in Rio Grande do Sul, by gender and age ranges, and whether suicide characteristics in the state are coherent with findings from previous studies. Methods: All data were collected from official secondary sources maintained by the national Brazilian and Rio Grande do Sul governments, covering a period from 2015 to 2019. Data included suicide deaths and population, divided by gender and age range. Sum totals, frequencies, odds ratios, and time series analyses were performed. Results: From 2015 to 2019, 6,287 people committed suicide in Rio Grande do Sul. Most of them were men and the most prevalent age band was from 50 to 59 years old. Men had higher suicide rates then women in all age ranges (p < 0.001) and in all months of the year, with an approximately 4-fold higher risk of committing suicide when compared to women. Men had a trending peak of suicide in January and December (p < 0.001), whereas women's suicide rates peaked in March and December (p = 0.001). Conclusion: There are monthly time trends and seasonal patterns of suicide rates in Rio Grande do Sul, varying by gender and age range. Gender differences occurred mainly in the first three months of the year, and the age pattern was more evident among individuals aged 60 years or older.