title: Heatwaves and Hospital Admissions for Mental Disorders in Northern Vietnam.
abstract: Studies in high-income countries have shown an association between heatwaves and hospital admissions for mental disorders. It is unknown whether such associations exist in subtropical nations like Vietnam. The study aim was to investigate whether hospital admissions for mental disorders may be triggered, or exacerbated, by heat exposure and heatwaves, in a low- and middle-income country, Vietnam. For this, we used data from the Hanoi Mental Hospital over five years (2008-2012) to estimate the effect of heatwaves on admissions for mental disorders. A zero-inflated negative binomial regression model accounting for seasonality, time trend, days of week, and mean humidity was used to analyse the relationship. Heatwave events were mainly studied as periods of three or seven consecutive days above the threshold of 35°C daily maximum temperature (90th percentile). The study result showed heatwaves increased the risk for admission in the whole group of mental disorders (F00-79) for more persistent heatwaves of at least 3 days when compared with non-heatwave periods. The relative risks were estimated at 1.04 (0.95-1.13), 1.15 (1.005-1.31), and 1.36 (1-1.90) for a one-, three- and seven-day heatwave, respectively. Admissions for mental disorders increased among men, residents in rural communities, and the elderly population during heatwaves. The groups of organic mental disorders, including symptomatic illnesses (F0-9) and mental retardation (F70-79), had increased admissions during heatwaves. The findings are novel in their focus on heatwave impact on mental diseases in a population habituating in a subtropical low- and middle-income country characterized by rapid epidemiological transitions and environmental changes.
authors.affiliation: Department of Public Health and Clinical Medicine, Unit of Epidemiology and Global Health, Umeå University, Sweden.
authors.forename: Phan Minh
authors.initials: PM
authors.lastname: Trang
authors.affiliation: Department of Public Health and Clinical Medicine, Unit of Epidemiology and Global Health, Umeå University, Sweden.
authors.forename: Joacim
authors.initials: J
authors.lastname: Rocklöv
authors.affiliation: Institute for Preventive Medicine and Public Health, Hanoi Medical University, Vietnam.
authors.forename: Kim Bao
authors.initials: KB
authors.lastname: Giang
authors.affiliation: Department of Psychiatry Clinical Sciences, Umeå University, Umeå, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Kullgren
authors.affiliation: Department of Public Health and Clinical Medicine, Unit of Epidemiology and Global Health, Umeå University, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Nilsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003625:Data Collection; D004636:Emergency Service, Hospital; D005260:Female; D006778:Hospitals, Psychiatric; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology*; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data*; D012044:Regression Analysis; D012307:Risk Factors; D012424:Rural Population; D012621:Seasons; D013997:Time Factors; D014744:Vietnam; D055815:Young Adult