An eight-year review of emergency presentations in Balikesir, Turkey, found no statistically significant day-to-day relationship between weather, air pollution and hospital visits after suicide attempts.
The study examined 1,413 visits coded as intentional self-harm at Balikesir Atatürk City Hospital between January 2017 and December 2024. Researchers compared daily visit counts with temperature, rainfall, sunlight, PM2.5, sulfur dioxide and ozone levels over the previous one to seven days.
None of those environmental measures significantly improved the prediction of daily visits in the study’s time-series models. All reported p-values were above 0.05.
What the study found
The 1,413 visits occurred across 2,922 days, or roughly one visit every two days. The average patient age was 26.9 years, with a standard deviation of 14.2 years. Women accounted for 904 visits, or 64.0%, and men for 509, or 36.0%.
Monthly rates were highest in May, at 4.6 per 100,000 people. June and December each had a rate of 4.5 per 100,000, as did March. January had the lowest rate, at 3.3 per 100,000, while August recorded 3.5 per 100,000.
Yearly rates varied as well. They peaked at 64.8 per 100,000 in 2019 and reached their lowest point, 37.0 per 100,000, in 2024.
Visits were more frequent on Wednesdays, Fridays and Saturdays, and markedly lower on Thursdays. The researchers noted that local social routines or weekly patterns in access to care could be possible explanations, but the study did not establish why this pattern occurred.
Why the result does not settle the broader question
The Balikesir research used an ecological time-series design. That means it compared area-level daily counts with environmental conditions over time; it could not show what any individual experienced or explain why a particular person came to the hospital.
It also covered one hospital and counted visits rather than distinct people. People treated elsewhere, or those who did not seek care, were not included. Weather data came from a state monitoring station in central Balikesir, while air-quality data came from one central station selected as the best match for the hospital’s urban catchment area. A single station may not represent conditions across the province.
The analysis focused on short-term effects over a seven-day window. It could miss cumulative exposure over months, heat waves, extreme events or non-linear effects. Humidity, daily temperature range and personal, social and economic factors were not included. The source also notes that relatively low daily counts could make a modest environmental effect difficult to detect.
How this compares with other research
Other research has reported small associations between environmental conditions and suicide deaths. A study covering 1,320,148 suicides across 341 locations in 12 countries found that risk generally rose with daily temperature and peaked at about 27°C, at 1.33 times the risk seen at the coldest temperatures.
A 2021 meta-analysis of 11 studies involving 283,550 suicides reported small increases in suicide deaths after higher air-pollution exposure, including 1.7% higher odds per 10 µg/m³ of PM2.5 averaged over the same day and the day before. The source says the pollution findings were fragile overall, with no same-day effect reported, signs of publication bias and only sulfur dioxide remaining when individual studies were removed.
Those studies primarily examined suicide deaths, whereas the Balikesir analysis examined hospital visits after suicide attempts. The difference in outcome, along with the large sample sizes needed to detect small daily effects, makes direct comparison difficult.
What the findings may mean for services
The researchers concluded that environmental influences, where they exist, are more likely to operate slowly or indirectly than as straightforward day-to-day triggers. Seasonal and weekly patterns may still help inform planning for emergency and crisis-service staffing and outreach, even though the study did not identify a significant short-term effect from the measured weather or pollution variables.
Overall, the findings argue against treating a single day’s temperature or air-quality reading as a reliable explanation for changes in suicide-attempt visits. They also do not rule out longer-term, indirect or context-dependent relationships.
AI tools were used to assist with the preparation of this article under our editorial standards.
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