title: Short-term effects of air temperature and mitochondrial DNA lesions within an older population.
abstract: Previous studies have linked both extreme and sub-optimal air temperature to cardiopulmonary morbidity and mortality, especially in older individuals. However, the underlying mechanisms are yet to be determined.
  
  
  
  We hypothesized that short-term increases in air temperature may induce blood mitochondrial DNA (mtDNA) lesions in older individuals, which could contribute to temperature-related pathogenesis.
  
  
  
  We repeatedly measured mtDNA lesions in blood samples from 654 participants in the Normative Aging Study from 1999 to 2013 (1142 observations) by quantitative long-amplicon polymerase chain reaction assay. Hourly temperature data were obtained from the Boston Logan Airport weather station (located approximately 12km from the clinical site). We calculated 2-, 7-, and 14-day moving averages of 24-hour mean and 24-hour variability of temperature. We fit covariate-adjusted linear-mixed models accounting for repeated measures to evaluate the association between short-term increases in mean and variability of temperature with mtDNA lesions within each season.
  
  
  
  Interquartile increases in 7- and 14-day moving averages of 24-hour mean temperature in summer were associated with a 0.17 (95% CI: 0.07, 0.27; p=0.0007) and 0.21 (95% CI: 0.10, 0.32; p=0.0001) increase in the number of mtDNA lesions per 10kb, respectively. Results were similar when we further adjusted for temperature variability. We also observed significant associations between increases in temperature variability and mtDNA lesions independent of mean air temperature. An interquartile range increase in the 7-day moving average of 24-hour standard deviation in summer was associated with a 0.19 (95% CI: 0.07, 0.31; p=0.0023) increase in the number of mtDNA lesions per 10kb.
  
  
  
  Short-term exposure to higher mean air temperature was associated with increased mtDNA lesions in older adults, supporting the hypothesis that sub-optimal meteorological conditions may induce pathophysiological responses among susceptible populations.
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Electronic address: chp950@mail.harvard.edu.
authors.forename: Cheng
authors.initials: C
authors.lastname: Peng
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Developmental Neurobiology, National Institute of Perinatology, Mexico City, Mexico.
authors.forename: Marco
authors.initials: M
authors.lastname: Sanchez-Guerra
authors.affiliation: Department of Statistics, Colorado State University, Fort Collin, CO, USA.
authors.forename: Ander
authors.initials: A
authors.lastname: Wilson
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Amar J
authors.initials: AJ
authors.lastname: Mehta
authors.affiliation: Department of Environmental Health, Mailman School of Public Health, Columbia University, New York, NY, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Antonella
authors.initials: A
authors.lastname: Zanobetti
authors.affiliation: Department of Environmental Health, Mailman School of Public Health, Columbia University, New York, NY, USA.
authors.forename: Kasey
authors.initials: K
authors.lastname: Brennan
authors.affiliation: Department of Environmental Health, Mailman School of Public Health, Columbia University, New York, NY, USA.
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Dereix
authors.affiliation: Department of Biostatistics, Harvard School of Public Health, Boston, MA, USA.
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.affiliation: Normative Aging Study, Veterans Affairs Boston Healthcare System, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Pantel
authors.initials: P
authors.lastname: Vokonas
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Channing Laboratory, Harvard Medical School, Boston, MA, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.affiliation: Department of Environmental Health, Mailman School of Public Health, Columbia University, New York, NY, USA.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Baccarelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001900:Boston; D004249:DNA Damage; D004272:DNA, Mitochondrial; D006801:Humans; D016014:Linear Models; D008297:Male; D012621:Seasons; D013696:Temperature
chemical_list: D004272:DNA, Mitochondrial