Cold and dry conditions acutely increase pediatric elevated blood pressure risk, with important effect modification by humidity, demonstrating that meteorological conditions are modifiable environmental hazards for cardiovascular health in children.
Key Findings
Results
Low ambient temperature (9.5°C) was significantly associated with increased elevated blood pressure (EBP) risk in children, with the strongest effect at lag 0.
At lag 0, low temperature (9.5°C) was associated with OR = 1.514 (95% CI: 1.179–1.946) for EBP risk.
The study used distributed lag nonlinear models (DLNMs) within a generalized linear mixed model framework.
The cohort included 7,390 Chinese children with 22,610 observations from the Shanghai Municipal Dynamic Cohort of Student Common Diseases (2021–2024).
The effect was nonlinear and lagged, with the peak adverse effect occurring at lag 0 (same day).
Results
Moderately high temperatures showed a protective effect against EBP risk at lag 0.
Moderately high temperatures were associated with OR = 0.809 (95% CI: 0.680–0.962) at lag 0.
This protective effect was observed in the short-term nonlinear analysis.
The finding suggests a nonlinear (non-monotonic) relationship between temperature and pediatric EBP.
Results
Relative humidity exhibited a nearly linear inverse association with pediatric EBP risk.
High humidity significantly reduced cumulative EBP risk over lag 0–7 days: OR = 0.584 (95% CI: 0.427–0.797).
Low humidity significantly elevated cumulative EBP risk over lag 0–7 days: OR = 3.210 (95% CI: 2.040–5.051).
The association between humidity and EBP was described as 'nearly linear' and inverse in direction.
The cumulative lag window examined was lag 0–7 days.
Results
Significant temperature-humidity interactions were identified, with low humidity amplifying the adverse effect of cold exposure and high humidity exacerbating risk under extreme heat.
Low humidity amplified the adverse cardiovascular effect of cold temperature exposure on EBP.
High humidity exacerbated EBP risk under extreme heat conditions.
These interactions suggest the joint meteorological environment, not temperature or humidity alone, determines pediatric cardiovascular risk.
The interaction was identified using the DLNM framework.
Results
Primary-school children and urban residents showed greater vulnerability to cold and dry meteorological conditions in subgroup analyses.
Subgroup analyses stratified by school level (primary vs. other) and residential setting (urban vs. non-urban).
Primary-school-aged children demonstrated greater susceptibility to cold and dry conditions compared to older children.
Urban residents were identified as more vulnerable than non-urban residents.
Sensitivity analyses confirmed the robustness of these subgroup findings.
Methods
The study design used a large longitudinal cohort with repeated measures to assess short-term meteorological effects on pediatric blood pressure.
The cohort comprised 7,390 Chinese children with 22,610 total observations collected between 2021 and 2024.
Data were sourced from the Shanghai Municipal Dynamic Cohort of Student Common Diseases.
Analytical approach used distributed lag nonlinear models (DLNMs) embedded within a generalized linear mixed model (GLMM) framework.
Childhood elevated blood pressure (EBP) was characterized as 'a recognized early marker of cardiovascular risk.'
What This Means
This research suggests that weather conditions — specifically cold temperatures and low humidity — can meaningfully raise the risk of elevated blood pressure in children within a short time frame (the same day or up to a week later). Using data from nearly 7,400 school-aged children in Shanghai tracked over three years, the researchers found that on cold days (around 9.5°C / ~49°F), children were about 50% more likely to have elevated blood pressure compared to moderate temperature days. In contrast, moderately warm temperatures appeared to have a mild protective effect. Low humidity was associated with more than a tripling of cumulative elevated blood pressure risk, while high humidity was associated with roughly a 40% reduction in that risk.
The study also found that temperature and humidity interact with each other: dry cold was especially harmful, while hot and humid conditions also raised risk. Younger, primary-school-aged children and children living in urban areas appeared to be more sensitive to these meteorological effects than other groups. These findings held up across multiple sensitivity analyses, suggesting the results are robust.
This research suggests that weather and climate conditions are not just background factors but active, short-term influences on children's cardiovascular health. The findings support the idea that schools and public health programs could use weather forecasts to anticipate periods of elevated cardiovascular risk for children, potentially informing climate-adaptive health strategies such as targeted monitoring or protective measures on cold, dry days.
Chu L, Yang D, Zheng K, Yang Y, Huang Y, Huang S, et al.. (2026). Pediatric blood pressure vulnerability to meteorological hazards: Lagged and nonlinear effects of temperature-humidity exposure in urban China.. Environmental research. https://doi.org/10.1016/j.envres.2026.124846