Nutritional Status and Tuberculosis Risk in Adult and Pediatric Household Contacts.
BACKGROUND
Studies show obesity decreases risk of tuberculosis (TB) disease. There is limited evidence on whether high body mass index also protects against TB infection; how very high body mass indices influence TB risk; or whether nutritional status predicts this risk in children. We assessed the impact of body mass index on incident TB infection and disease among adults and children.


RESULTS
We conducted a prospective cohort study among household contacts of pulmonary TB cases in Lima, Peru. We determined body mass index at baseline and followed participants for one year for TB infection and disease. We used Cox proportional regression analyses to estimate hazard ratios for incident TB infection and disease. We enrolled 14,044 household contacts, and among 6853 negative for TB infection and disease at baseline, 1787 (26.1%) became infected. A total of 406 contacts developed secondary TB disease during follow-up. Body mass index did not predict risk of TB infection but overweight household contacts had significantly decreased risk of TB disease (HR 0.48; 95% CI 0.37-0.64; p <0.001) compared to those with normal weight. Among adults, body mass index ≥ 35 kg/m2 continued to predict a lower risk of TB disease (HR 0.30; 95% CI 0.12-0.74; p 0.009). We found no association between high body mass index and TB infection or disease among children under 12 years of age.


CONCLUSIONS
High body mass index protects adults against TB disease even at levels ≥ 35 kg/m2. This protective effect does not extend to TB infection and is not seen in children.
Department of Internal Medicine, Division of General Internal Medicine, The University of Texas Health Science Center at Houston, McGovern Medical School, Houston, Texas, United States of America.
Omowunmi
http://orcid.org/0000-0003-0665-5393
O
Aibana
Department of Social and Environmental Health Research, London School of Hygiene & Tropical Medicine, London, United Kingdom.
Xeno
X
Acharya
Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America.
Chuan-Chin
CC
Huang
Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.|Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Mercedes C
MC
Becerra
Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.|Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Jerome T
JT
Galea
Department of Pediatrics, Alpert School of Medicine of Brown University, Providence, Rhode Island, United States of America.|Center for International Health Research, Rhode Island Hospital, Providence, Rhode Island, United States of America.
Silvia S
SS
Chiang
Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Carmen
C
Contreras
Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Roger
R
Calderon
Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Rosa
R
Yataco
Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.|Department of Internal Medicine, Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts, United States of America.
Gustavo E
GE
Velásquez
Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Karen
K
Tintaya
Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Judith
J
Jimenez
Partners In Health / Socios En Salud Sucursal Peru, Lima, Peru.
Leonid
L
Lecca
Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America.
Megan B
MB
Murray
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing; D018562:Disease Transmission, Infectious / Q000706:statistics & numerical data; D005191:Family Characteristics; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009752:Nutritional Status; D010568:Peru / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission*; D055815:Young Adult