Mortality and Years of Life Lost from Waterborne and Water-Related Infectious Diseases in Costa Rica, 2000–2023: A Nationwide Ecological Study

Waterborne, water-related, and foodborne infectious diseases remain preventable causes of mortality, but long-term evidence on their demographic, spatial, and premature mortality burden is limited in Costa Rica. This ecological population-based study described deaths classified under selected ICD-10 codes during 2000–2023 using official mortality and population data. Crude and age-standardized mortality rates, years of life lost (YLL), and YLL rates were estimated by time, sex, age group, and geographic area. A total of 2450 deaths were identified. Diarrhea and gastroenteritis of presumed infectious origin accounted for 1537 deaths (62.7%), followed by other bacterial intestinal infections (23.8%) and leptospirosis (7.0%). Annual crude mortality rates ranged from 1.28 per 100,000 population in 2021 to 3.03 in 2017. Mortality showed a bimodal age pattern, with the highest rate among persons aged 75 years or older and a relevant early-childhood component. A total of 57,625.5 YLL were estimated, with the largest burden among children aged 0–4 years and the highest provincial YLL rates in Limón, Puntarenas, and Guanacaste. These findings support incorporating premature mortality metrics into environmental health surveillance, although the ecological design does not identify exposure sources or causal determinants.