Effects of meteorological factors on incidence of lactational mastitis in Nanjing:based on a distributed lag nonlinear model
WANG Hui-yuan
HE Yu-heng
ZHANG Chun-zi
DU Ya-han
TAN Rong-rong
PU Dan-hua
WU Jie
Abstract：Objective To explore the association between various meteorological factors and the risk of lactational mastitis in Nanjing.Methods The patients with lactational mastitis admitted to the First Affiliated Hospital of Nanjing Medical University between January 1,2023 and December 31,2023 were enrolled as study subjects.Epidemiological methods were used to describe the epidemic characteristics of lactational mastitis.The daily data of meteorological factors during the study period were obtained from Nanjing Meteorological Observation Center.Then a time series database was established,and Spearman rank correlation analysis was used to analyze the correlation between daily number of cases of lactational mastitis and meteorological factors.Distributed lag nonlinear model(DLNM)was built to quantitatively analyze and evaluate the exposure-lag effects of various meteorological factors on the incidence of lactational mastitis as well as the incidence risk of lactational mastitis under extreme meteorological conditions.Results(1)A total of 282 lactational mastitis patients were included in the study.The incidence of lactational mastitis showed an overall trend of first increasing and then decreasing in 2023,showing a periodical bimodal structure and a significant seasonal effect,with minor peaks in May and December.(2)The risk of lactational mastitis decreased as air pressure increased.When exposed to low pressure,the relative risk of lactational mastitis peaked on the 9th lag day(RR 1.14,95％CI 1.01-1.28).When exposed to high pressure,the relative risk of lactational mastitis continued to increase within the 14 lag days.(3)The risk of lactational mastitis increased as temperature rose.When exposed to low temperature,the relative risk of lactational mastitis gradually increased during the lag period of 0～14 days.However,when exposed to high temperature,the relative risk of lactational mastitis peaked on the 8th day(RR 1.07,95％CI 0.99-1.16).Conclusions Daily mean pressure and highest daily temperature have a non-linear relationship with the incidence of lactational mastitis in Nanjing,and there is a significant lag effect.Exposure to low pressure and high temperature significantly increases the incidence risk of lactational mastitis.
Keywords：lactational mastitismeteorological factorsdistributed lag nonlinear model
Publication Date：2025-09-02
Online Publishing Date：2025-10-20(First online date of this platform, not the publication date of the document)
Pages：5( 936-940 )