[Distributed lag effects on the relationship between daily mean temperature and the incidence of bacillary dysentery in Lanzhou city].

OBJECTIVE

To discuss the lag effects of daily average temperature on the daily cases of bacillary dysentery in Lanzhou city.

METHODS

The data of daily cases of bacillary dysentery were collected during 2008 and 2015 in the city, and the meteorological data at the same period was integrated. The distributed lag non-linear model was used to analyze the relevance between daily average temperature and the daily cases of bacillary dysentery.

RESULTS

The exposure response relationship between the daily temperature and the incidence of bacillary dysentery was "J" type, the lowest incidence temperature was 17 °C, and the effect of high temperature on different gender and age groups was higher than that of the intermediate effect. The effect of high temperature and intermediate effect on the male and female groups showed an acute effect, the effect of the day was the highest, followed by fluctuations in temperature, and the greater the impact on women. In different age groups, high temperature effect and the intermediate effect of bacterial dysentery in 0-3 years old groups were the biggest; the effects of high and intermediate temperature on people aged 0-3 and 19-64 year all showed acute effects, which were the maximum value at the day, then decreased volatility; and for people aged over 65 years, the day after the onset, decreases and then increases slowly. There were obviously increasing risks of bacillary dysentery both the high temperature (32 °C) and the middle temperature (26 °C) with respect to 17 °C. The accumulative effects were highest at lag14 days, and the RR (95%CI) values of middle temperature was 2.30 (1.53-3.13), 2.45 (1.65-3.30), 2.41 (1.59-3.28), 2.54 (1.40-3.79), 1.82 (0.41-3.43), 1.98 (1.11-2.93), and 1.73 (0.68-2.88) among the males, females, 0-3 years old, 4-11 years old, 12-18 years old, 19-64 years old and over 65 years old people, respectively; while the high temperature was 2.93 (1.38-4.69), 3.08 (1.48- 4.90), 3.26 (1.60-5.16), 3.12 (1.06-5.56), 1.94 (0.73-5.39), 2.31 (0.54-4.36), and 2.06 (0.02-4.51), respectively.

CONCLUSION

The high temperature may increase risks of bacillary dysentery, and the females and younger people were the sensitive population. Meteorological factors play an important role in the occurrence and development of bacillary dysentery in Lanzhou. The incidence of bacillary dysentery is affected by multiple meteorological factors, but the primary one is high temperature. The temperature has not a direct effect on the incidence of bacillary dysentery, but an indirect influence in different populations through the impacts of various aspects of the incidence of bacterial dysentery (residents living habits, communication channels and the habits of the susceptible population).