BACKGROUND: High ambient temperatures are a risk factor for nephrolithiasis, but the precise relationship between temperature and kidney stone presentation is unknown.
OBJECTIVES: Our objective was to estimate associations between mean daily temperature and kidney stone presentation according to lag time and temperatures.
METHODS: Using a time series design and distributed lag non-linear models, we estimated the relative risk (RR) of kidney stone presentation associated with mean daily temperatures, including cumulative RR for a 20-day period, and RR for individual daily lags through 20 days. Our analysis used MarketScan data for 60,433 patients who presented for evaluation or treatment of kidney stones from 2005-2011 in Atlanta, Chicago, Dallas, Los Angeles, and Philadelphia.
RESULTS: Associations between mean daily temperature and kidney stone presentation were not monotonic, and there was variation in the exposure-response curve shapes and the strength of associations at different temperatures. However, in most cases RRs increased for temperatures above the reference value of 10°C. The cumulative RR for a daily mean temperature of 30°C versus 10°C was 1.38 in Atlanta (95% CI: 1.07, 1.79), 1.37 in Chicago (95% CI: 1.07, 1.76), 1.36 in Dallas (95% CI: 1.10, 1.69), 1.11 in Los Angeles (95% CI: 0.73, 1.68), and 1.47 in Philadelphia (95% CI: 1.00, 2.17). Kidney stone presentations also were positively associated with temperatures < 2°C in Atlanta, and < 10°C in Chicago and Philadelphia. In 4 cities, the strongest association between kidney stone presentation and a daily mean temperature of 30 versus 10°C was estimated for lags ≤ 3 days.
CONCLUSIONS: In general, kidney stone presentations increased with higher daily mean temperatures, with the strongest associations estimated for lags of only a few days. These findings further support an adverse effect of high temperatures on nephrolithiasis.
Written by:
Tasian GE, Pulido JE, Gasparrini A, Saigal CS, Horton BP, Landis JR, Madison R, Keren R. Are you the author?
Department of Surgery, Division of Urology, The Children's Hospital of Philadelphia; Perelman School of Medicine at The University of Pennsylvania; and Center for Pediatric Clinical Effectiveness, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Perelman School of Medicine at The University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, England; Department of Urology, University of California, Los Angeles, Los Angeles, California; RAND Corporation; Santa Monica, California, USA; Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey, USA; Division of Earth Sciences and Earth Observatory of Singapore, Nanyang Technological University, 639798, Singapore; Department of Epidemiology and Biostatistics, Perelman School of Medicine at The University of Pennsylvania, Philadelphia, Pennsylvania, USA; RAND Corporation; Santa Monica, California, USA; Center for Pediatric Clinical Effectiveness, The Children's Hospital of Philadelphia; Department of Epidemiology and Biostatistics, Perelman School of Medicine at The University of Pennsylvania; and Department of Pediatrics The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Reference: Environ Health Perspect. 2014 Jul 10. Epub ahead of print.
doi: 10.1289/ehp.1307703
PubMed Abstract
PMID: 25009122