Wingfield, Tom ORCID: 0000-0001-8433-6887, Schumacher, Samuel G, Sandhu, Gurjinder, Tovar, Marco A, Zevallos, Karine, Baldwin, Matthew R, Montoya, Rosario, Ramos, Eric S, Jongkaewwattana, Chulanee, Lewis, James J et al (show 3 more authors)
(2014)
The Seasonality of Tuberculosis, Sunlight, Vitamin D, and Household Crowding.
Journal of Infectious Diseases, 210 (5).
pp. 774-783.
Text
Seasonality of TB JID.pdf - Published version Download (389kB) |
Abstract
Background. Unlike other respiratory infections, tuberculosis diagnoses increase in summer. We performed an ecological analysis of this paradoxical seasonality in a Peruvian shantytown over 4 years. Methods. Tuberculosis symptom-onset and diagnosis dates were recorded for 852 patients. Their tuberculosis-exposed cohabitants were tested for tuberculosis infection with the tuberculin skin test (n = 1389) and QuantiFERON assay (n = 576) and vitamin D concentrations (n = 195) quantified from randomly selected cohabitants. Crowding was calculated for all tuberculosis-affected households and daily sunlight records obtained. Results. Fifty-seven percent of vitamin D measurements revealed deficiency (<50 nmol/L). Risk of deficiency was increased 2.0-fold by female sex (P < .001) and 1.4-fold by winter (P < .05). During the weeks following peak crowding and trough sunlight, there was a midwinter peak in vitamin D deficiency (P < .02). Peak vitamin D deficiency was followed 6 weeks later by a late-winter peak in tuberculin skin test positivity and 12 weeks after that by an early-summer peak in QuantiFERON positivity (both P < .04). Twelve weeks after peak QuantiFERON positivity, there was a midsummer peak in tuberculosis symptom onset (P < .05) followed after 3 weeks by a late-summer peak in tuberculosis diagnoses (P < .001). Conclusions. The intervals from midwinter peak crowding and trough sunlight to sequential peaks in vitamin D deficiency, tuberculosis infection, symptom onset, and diagnosis may explain the enigmatic late-summer peak in tuberculosis.
Item Type: | Article |
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Uncontrolled Keywords: | crowding, household, seasonality, sunlight, tuberculosis, vitamin D |
Depositing User: | Symplectic Admin |
Date Deposited: | 19 Oct 2016 14:29 |
Last Modified: | 19 Jan 2023 07:28 |
DOI: | 10.1093/infdis/jiu121 |
Related URLs: | |
URI: | https://livrepository.liverpool.ac.uk/id/eprint/3003879 |