Sunshine and suicide at the tropic of Capricorn, São Paulo, Brazil, 1996-2004

Abstract

Several studies have confi rmed seasonal variation in suicide rates according to hours of sunshine. The suicide pattern was assessed in São Paulo, southeastern Brazil, at the tropic of Capricorn from 1996 to 2004. Poisson regression was employed to estimate parameters of seasonality, as well as to verify associations for each day between daylight duration and suicide. During the nine-year study period, there were 3,984 suicides (76.9% in men; median age=38.7 years old). Seasonal averages of suicides were similar, as were monthly averages. Poisson regression did not reveal any association between suicide rates and hours of sunshine (p=0.45) for both sexes. In conclusion, no seasonal pattern was observed for suicides. RESUMOEstudos epidemiológicos têm confi rmado que as taxas de suicídio apresentam variação sazonal relacionada às horas de insolação. O padrão de suicídios foi analisado na cidade de São Paulo, Brasil, no trópico de Capricórnio, de 1996 a 2004. A regressão de Poisson foi utilizada para estimar padrões de sazonalidade, bem como verifi car a associação dia-a-dia entre duração da insolação e suicídio. Durante os nove anos houve 3.984 suicídios (76,9% homens; mediana de idade=38,7 anos). As médias de suicídio por estação do ano e por mês de suicídio foram similares. Segundo a regressão de Poisson, não houve associação entre insolação e suicídio (p=0,45) para ambos os sexos. Conclui-se que não houve padrão sazonal de suicídios na cidade de São Paulo. DESCRITORES:

Suicide and meteorological factors in São Paulo, Brazil, 1996-2011: a time series analysis

“…The former found an association with sunshine during up to 9 days preceding suicide, 12 while Deisenhammer et al found a positive association between daily high temperature and suicide in Tyrol, Austria. 24 Studies using GLM in São Paulo 18 and in a northern province of Finland 27 revealed no association between meteorological factors and suicide. Possible explanations for the contradiction between findings and those of this previous study carried out in Sã o Paulo include different time span (1996 to 2004), time unit (day), and statistical method (GLM).…”

“…7,8 In Brazil, Benedito-Silva et al 16 found a seasonal distribution of suicide, peaking in spring/summer, but only in the southern states. Specifically in the city of São Paulo, Bando and Volpe reported a significant circannual cycle peaking in spring/summer for both men and women from 1996 to 2010, 17 while Nejar et al 18 did not find seasonality or any association between suicide and meteorological factors in São Paulo from 1996 to 2004.…”

“…12,[21][22][23] Research conducted in Asia, Europe, and the Americas has explored a short-term association between meteorological factors and suicide. [10][11][12]18,[24][25][26][27] A time-series regression approach applying a generalized additive model (GAM) has typically been used in studies exploring the association between environmental factors and mortality 28,29 ; however, there are few studies about suicide. A study performed in Korea using the GAM, adjusted for confounding factors, observed a 1.4% increase in suicide with each 1 o C increase in daily mean temperature.…”

“…10 In Brazil, only one study investigated this issue, in São Paulo, and found no association between weather conditions and suicide. 18 Considering the lack of reports from intertropical latitudes on this issue, and the particular scarcity of GAMbased research, we aimed to examine the association between meteorological factors and suicide in the city of Sã o Paulo, Brazil, to add further evidence to this matter. 30 and is mostly urban.…”

Vitamin D status in a sunny country: Where has the sun gone?

“…It is located at 23 34 0 S, with a subtropical climate, and with a considerable sun radiation across the year (from 11.7 MJ/m 2 in June to 20.2 MJ/m 2 in December). 8 However, air pollution, which has been previously linked to hypovitaminosis D in other countries, 9 is highly prevalent in this city 10 , as is a sedentary life style. 11 Therefore, the objective of our study was to determine the prevalence of hypovitaminosis D in a sample of a normal Brazilian population after the winter and after the summer.…”