Impact of precipitation patterns on the risk of hand, foot, and mouth disease in Southwest China: insight from a disease burden perspective.

BACKGROUND

Precipitation is regarded as a pivotal upstream factor in the control of the hand, foot, and mouth disease (HFMD) burden. However, the current evidence on the direction and magnitude of precipitation patterns on HFMD burden remains unclear.

METHODS

We conducted a population-based ecological time-series study using daily HFMD cases and meteorological data from 88 counties in Guizhou, China, between 2012 and 2019. Weekly precipitation with the precipitation concentration degree was combined to define 35 distinct precipitation patterns. The HFMD burden was quantified using the years lived with disability (YLD) metric. The distributed lag non-linear models were used to evaluate the impact and risk thresholds of precipitation patterns regarding the attributable HFMD burden.

RESULTS

Among 524,100 reported HFMD cases, the total YLD was 403.3 person-years. As precipitation intensity increased, the maximum cumulative relative risk (RR) for HFMD burden reached 1.023 (95% confidence interval: 1.000–1.047). We identified three high-risk precipitation patterns: (1) concentrated precipitation below 50 mm, (2) dispersed precipitation below 150 mm, and (3) normal precipitation above 200 mm. The pooled RR and attributable YLD burden of the high-risk precipitation patterns were 1.026 (1.016–1.036) and 20.92 (11.21–30.31) person-years.

CONCLUSION

The complex precipitation patterns characterized by frequency-intensity combinations are linked to higher HFMD burden among children, with pattern-specific risk thresholds identified across these patterns. To reduce this burden, enhanced surveillance and climate-adaptive public health actions are recommended, particularly during periods of concentrated light precipitation, dispersed moderate precipitation, and evenly distributed extreme precipitation.