Temperature variation and preterm birth among live singleton deliveries in Shenzhen, China: A time-to-event analysis

Changchang Li; Michael S Bloom; Shao Lin; Meng Ren; Shakoor Hajat; Qiong Wang; Wangjian Zhang; Hung Chak Ho; Qingguo Zhao; Yan Lin; Cunrui Huang

doi:10.1016/j.envres.2021.110834

Temperature variation and preterm birth among live singleton deliveries in Shenzhen, China: A time-to-event analysis

Environ Res. 2021 Apr:195:110834. doi: 10.1016/j.envres.2021.110834. Epub 2021 Feb 3.

Authors

Changchang Li¹, Michael S Bloom², Shao Lin³, Meng Ren⁴, Shakoor Hajat⁵, Qiong Wang⁶, Wangjian Zhang⁷, Hung Chak Ho⁸, Qingguo Zhao⁹, Yan Lin¹⁰, Cunrui Huang¹¹

Affiliations

¹ Department of Sexually Transmitted Diseases Prevention and Control, Southern Medical University, No. Lujing Road, Guangzhou, 510095, China; Department of Health Policy and Management, School of Public Health, Sun Yat-sen University, No.74 Zhongshan Road #2, Guangzhou, 510080, China. Electronic address: lichch8@mail2.sysu.edu.cn.
² Departments of Environmental Health Sciences and Epidemiology and Biostatistics, University at Albany, State University of New York, Rensselaer, NY, USA; Department of Global and Community Health, George Mason University, Fairfax, VA, USA. Electronic address: mbloom22@gmu.edu.
³ Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Rensselaer, NY, USA. Electronic address: slin@albany.edu.
⁴ Department of Health Policy and Management, School of Public Health, Sun Yat-sen University, No.74 Zhongshan Road #2, Guangzhou, 510080, China. Electronic address: renm23@mail2.sysu.edu.cn.
⁵ Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, USA. Electronic address: Shakoor.Hajat@lshtm.ac.uk.
⁶ Department of Health Policy and Management, School of Public Health, Sun Yat-sen University, China; Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, School of Public Health, Sun Yat-sen University, China. Electronic address: wangqiong@mail.sysu.edu.cn.
⁷ Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, Rensselaer, NY, USA. Electronic address: wzhang27@albany.edu.
⁸ Department of Urban Planning and Design, The University of Hong Kong, Hong Kong, China; School of Geography and Remote Sensing, Guangzhou University, Guangzhou, China. Electronic address: hcho21@hku.hk.
⁹ Epidemiology Research Office of Key Laboratory of Male Reproduction and Genetics (National Health Commission), Family Planning Institute of Guangdong Province／Family Planning Special Hospital of Guangdong Province, Guangzhou, China. Electronic address: zqgfrost@126.com.
¹⁰ Department of Children Health Care, Shenzhen Women and Children Hospital, China. Electronic address: 953019968@qq.com.
¹¹ Department of Health Policy and Management, School of Public Health, Sun Yat-sen University, No.74 Zhongshan Road #2, Guangzhou, 510080, China; Shanghai Key Laboratory of Meteorology and Health, Shanghai Meteorological Service, Shanghai, 200030, China; School of Public Health, Zhengzhou University, Zhengzhou, 450001, China. Electronic address: huangcr@mail.sysu.edu.cn.

PMID: 33548292
DOI: 10.1016/j.envres.2021.110834

Abstract

Objective: Ambient temperature extremes due to heat exposure was an established risk factor for preterm birth (<37 gestational weeks). However, there is insufficient epidemiological evidence on the effects of temperature variation(TV), although TV is also associated with heat exposure and can influence human health risk. This study aimed to investigate the relationship between inter- and intraday TV and preterm birth (PTB).

Method: A total of 1,388,994 live singleton births were collected from January 2003 to December 2012, from the Shenzhen Birth registry system. Daily temperature range (DTR) was defined as the difference between the highest and lowest recorded daily temperature. Intraday TV was defined as the maximum daily diurnal temperature range in a given week (Max-DTR). Inter-day TV was defined as the maximum increase or decrease in daily mean temperature between days t and t-1in a given week; either an increase (Temp-inc) or a decrease (Temp-dec). We used Cox proportional hazards models to estimate TV-related PTB risks during the first trimester, the second trimester, and in late pregnancy.

Results: The maximum values for DTR, Temp-inc, and Temp-dec were 17 °C, 8 °C and 11 °C, respectively. The greatest TV-related PTB risk occurred in the second trimester, with 5.8% (95%CI: 3.3%, 8.3%), 23.7% (95%CI: 19.6%, 27.9%), and 4.4% (95%CI: 1.8%, 7.1%) differences per 1 °C increase in Max-DTR, Temp-inc, and Temp-dec, respectively. Greater TV was associated with elevated PTB risk during the warm season. The association between TV and PTB was modified by seasons, maternal education and chronic conditions.

Conclusions: Sharp TV is a likely risk factor for PTB. Policy makers and clinicians should recognize the potential role of TV in the etiology of PTB so that interventions can be designed to protect pregnant women and their fetuses against extreme temperatures.

Keywords: Ambient temperature; Diurnal temperature range; Preterm birth; Temperature changes between neighboring days; Temperature variation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

China / epidemiology
Female
Humans
Infant, Newborn
Pregnancy
Pregnancy Trimester, Second
Premature Birth* / epidemiology
Risk Factors
Seasons
Temperature

Grants and funding

R15 ES028000/ES/NIEHS NIH HHS/United States