title: The effects of heat stress and its effect modifiers on stroke hospitalizations in Allegheny County, Pennsylvania.
abstract: OBJECTIVE
  Heat has been known to increase the risk of many health endpoints. However, few studies have examined its effects on stroke. The objective of this case-crossover study is to investigate the effects of high heat and its effect modifiers on the risk of stroke hospitalization in Allegheny County, Pennsylvania.
  
  
  METHODS
  We obtained data on first stroke hospitalizations among adults ages 65 and older and daily meteorological information during warm seasons (May-September) from 1994 to 2000 in Allegheny County, Pennsylvania. Using conditional multiple logistic regressions, the effects of heat days (any day with a temperature greater than the 95th percentile) and heat wave days (at least two continuous heat days) on the risk of stroke hospitalization were investigated. The potential interactions between high heat and age, type of stroke, and gender were also examined.
  
  
  RESULTS
  Heat day and heat wave at lag-2 day were significantly associated with an increased risk for stroke hospitalization (OR 1.121, 95 % CI 1.013-1.242; OR 1.173, 95 % CI 1.047-1.315, respectively) after adjusting for important covariates. In addition, having two or more heat wave days within the 4 day window prior to the event was also significantly associated with an increased risk (OR 1.119, 95 % CI 1.004, 1.246) compared to having no heat wave days during the period. The effect of high heat on stroke was more significant for ischemic stroke, men, and subjects ages 80 years or older.
  
  
  CONCLUSIONS
  Our study suggests that high heat may have adverse effects on stroke and that some subgroups may be particularly susceptible to heat.
authors.affiliation: Department of Epidemiology, College of Public Health and Health Professions, University of Florida, 101 S. Newell Drive, Room 3119, Gainesville, FL, 32610-0182, USA.
authors.forename: Sandie
authors.initials: S
authors.lastname: Ha
authors.forename: Evelyn O
authors.initials: EO
authors.lastname: Talbott
authors.forename: Haidong
authors.initials: H
authors.lastname: Kan
authors.forename: Cindy A
authors.initials: CA
authors.lastname: Prins
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution / Q000032:analysis; D018592:Cross-Over Studies; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D018882:Heat Stress Disorders / Q000453:epidemiology*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010414:Pennsylvania / Q000453:epidemiology; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D020521:Stroke / Q000453:epidemiology*
references.citation: Epidemiology. 2005 Nov;16(6):717-26
references.pmid: 16222160
references.citation: Environ Res. 2013 Jul;124:35-42
references.pmid: 23643292
references.citation: Environ Health. 2012 Aug 21;11:56
references.pmid: 22909034
references.citation: Int J Biometeorol. 2012 Jul;56(4):569-81
references.pmid: 21975970
references.citation: Int J Epidemiol. 2002 Aug;31(4):825-30
references.pmid: 12177030
references.citation: Am Fam Physician. 2011 Jun 1;83(11):1325-30
references.pmid: 21661715
references.citation: Ig Sanita Pubbl. 2008 Nov-Dec;64(6):735-72
references.pmid: 19219085
references.citation: Int J Biometeorol. 2008 Mar;52(4):291-9
references.pmid: 17929062
references.citation: Neurochem Int. 2012 Jan;60(2):208-12
references.pmid: 22122807
references.citation: Stroke. 2002 Jul;33(7):1751-7
references.pmid: 12105347
references.citation: PLoS One. 2013 Apr 30;8(4):e62059
references.pmid: 23646115
references.citation: Sci Total Environ. 2011 Dec 1;410-411:41-6
references.pmid: 22018962
references.citation: Am J Epidemiol. 2010 Nov 1;172(9):1053-61
references.pmid: 20829270
references.citation: Int J Biometeorol. 2013 Jul;57(4):535-44
references.pmid: 22872184
references.citation: Expert Rev Neurother. 2010 Feb;10(2):243-9
references.pmid: 20136380
references.citation: Environ Res. 2011 Nov;111(8):1192-200
references.pmid: 21816396
references.citation: Eur J Epidemiol. 2005;20(8):693-8
references.pmid: 16151883
references.citation: Semin Neurol. 2005 Sep;25(3):307-14
references.pmid: 16170743
references.citation: Epidemiology. 2005 Nov;16(6):715-6
references.pmid: 16222159
references.citation: Environ Health Perspect. 2006 Sep;114(9):1318-24
references.pmid: 16966082
references.citation: Int J Hyperthermia. 2003 May-Jun;19(3):373-84
references.pmid: 12745976
references.citation: Stroke. 1996 Sep;27(9):1459-66
references.pmid: 8784113
references.citation: J Occup Environ Med. 2009 Jan;51(1):26-32
references.pmid: 19136870
references.citation: Am J Respir Crit Care Med. 2009 Mar 1;179(5):383-9
references.pmid: 19060232
references.citation: N Engl J Med. 1999 Feb 11;340(6):448-54
references.pmid: 9971870
references.citation: Int J Biometeorol. 2008 Mar;52(4):301-10
references.pmid: 18030502
references.citation: Epidemiology. 2009 Sep;20(5):738-46
references.pmid: 19593155
references.citation: BMJ. 2012 Dec 13;345:e8050
references.pmid: 23243290
references.citation: Stroke. 2006 Apr;37(4):951-7
references.pmid: 16527994
references.citation: Environ Health. 2009 Sep 16;8:40
references.pmid: 19758453
references.citation: Environ Health Perspect. 2011 Dec;119(12):1681-90
references.pmid: 21816703
references.citation: Environ Res. 2010 Feb;110(2):152-61
references.pmid: 20060520
references.citation: Environ Health Perspect. 2011 Feb;119(2):210-8
references.pmid: 21084239
references.citation: Int J Health Geogr. 2010 Feb 08;9:5
references.pmid: 20144187
references.citation: Circ J. 2013;77(7):1854-61
references.pmid: 23595035
references.citation: Int J Biometeorol. 2008 Jan;52(3):223-9
references.pmid: 17960427
references.citation: Maturitas. 2011 Jun;69(2):99-105
references.pmid: 21477954
references.citation: Annu Rev Public Health. 2008;29:41-55
references.pmid: 18031221
references.citation: Trans Am Clin Climatol Assoc. 2009;120:113-7
references.pmid: 19768168
references.citation: Epidemiology. 2004 Nov;15(6):755-61
references.pmid: 15475726
references.citation: Environ Health. 2012 Sep 21;11:70
references.pmid: 22998927
references.citation: Adv Med Sci. 2007;52 Suppl 1:112-4
references.pmid: 18229645
references.citation: Int J Neurosci. 2002 Aug;112(8):959-63
references.pmid: 12448836
references.citation: J Environ Sci Eng. 2004 Apr;46(2):143-50
references.pmid: 16649605
references.citation: Epidemiology. 2003 Jul;14(4):473-8
references.pmid: 12843774
references.citation: Intensive Care Med. 2009 Aug;35(8):1454-8
references.pmid: 19404610
references.citation: Int J Public Health. 2010 Apr;55(2):113-21
references.pmid: 19771392
references.citation: Public Health Rep. 1990 May-Jun;105(3):283-9
references.pmid: 2113688
references.citation: Sci Total Environ. 2011 Nov 15;409(24):5260-7
references.pmid: 21975004
references.citation: J Epidemiol Community Health. 2011 Sep;65(9):829-31
references.pmid: 21097937
references.citation: Int J Stroke. 2009 Feb;4(1):19-20
references.pmid: 19236492
references.citation: Stroke. 1989 Jan;20(1):65-9
references.pmid: 2911837
references.citation: Scand J Public Health. 2010 Dec;38(8):826-37
references.pmid: 20688791
references.citation: Gerontology. 2012;58(4):289-95
references.pmid: 22085834
references.citation: Zhonghua Liu Xing Bing Xue Za Zhi. 2004 Nov;25(11):962-6
references.pmid: 15769329
references.citation: Int J Biometeorol. 2009 Nov;53(6):535-41
references.pmid: 19506912
references.citation: Environ Health Perspect. 2012 Jan;120(1):19-28
references.pmid: 21824855
references.citation: Am J Disaster Med. 2007 Jan-Feb;2(1):33-42
references.pmid: 18268873
references.citation: Environ Health Perspect. 2003 Aug;111(10):1312-7
references.pmid: 12896852
references.citation: Environ Health Prev Med. 2012 Jan;17(1):77-80
references.pmid: 21611887
references.citation: Am J Respir Crit Care Med. 2011 Oct 1;184(7):828-35
references.pmid: 21700913
references.citation: J Clin Epidemiol. 2004 Jul;57(7):749-57
references.pmid: 15358404
references.citation: Occup Environ Med. 2007 Jul;64(7):439-45
references.pmid: 17409181
references.citation: Environ Pollut. 2011 Jul;159(7):1789-93
references.pmid: 21511376
references.citation: Int J Biometeorol. 2012 Sep;56(5):865-72
references.pmid: 21915799