title: Seasonality of tuberculosis in Israel, 2001-2011.
abstract: Several studies have suggested that the incidence of tuberculosis (TB) varies with the seasons.
  
  
  
  To determine the seasonality of TB in Israel and to explore possible associations with climatic variables.
  
  
  
  Laboratory-confirmed TB cases reported between 2001 and 2011 in individuals resident in Israel for at least 1 year before diagnosis were included in the study. Climatic variables included average temperature and average ultraviolet radiation. The mean serum 25-hydroxyvitamin D level of the population was also recorded.
  
  
  
  Of all 2653 TB cases, incidence peaked during spring (n = 712) and reached its nadir during the fall (n = 577), with a case proportion amplitude (CPA) of 5.1% (P = 0.036). Individuals born in the Horn of Africa exhibited a CPA of 9.5% (P = 0.077). Mean population 25-hydroxyvitamin D level was significantly correlated with the seasonal pattern of the disease. Southern Israel had the highest global radiation and, counter-instinctively, the highest TB incidence.
  
  
  
  TB exhibited a seasonal tendency in Israel, with the spring peak/fall nadir pattern found elsewhere. Vitamin D is suspected to be an explanatory variable for this seasonal phenomenon. The finding that the highest incidence is in the area receiving the highest global radiation suggests population-related vulnerability to vitamin D deficiency.
authors.affiliation: The Hebrew University-Hadassah Medical School, Jerusalem.
authors.forename: I
authors.initials: I
authors.lastname: Margalit
authors.affiliation: The Hebrew University-Hadassah Medical School, Jerusalem, Department of Clinical Microbiology & Infectious Diseases, Hadassah-Hebrew University Medical Centre, Jerusalem.
authors.forename: C
authors.initials: C
authors.lastname: Block
authors.affiliation: Ramla Department of Health, Ministry of Health, Ramla, School of Public Health, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Z
authors.initials: Z
authors.lastname: Mor
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007557:Israel / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012621:Seasons; D014376:Tuberculosis / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D