Early Childhood TB Linked to Lung Function and Growth Deficits in Older Children

Pulmonary tuberculosis (PTB) in early childhood is associated with an increased risk for growth impairment, subsequent wheezing, and lung function deficits in later childhood, according to a study in the American Journal of Respiratory and Critical Care Medicine.

Research is lacking on whether children may have post-TB health impairments, and whether such impairments may involve growth and/or wheezing as well as lung function. Researchers therefore longitudinally assessed the effects of early-life TB on lung health, growth, and wheezing throughout childhood in participants from the Drakenstein Child Health Study, a birth cohort of 1143 children born to women in Cape Town, South Africa, who were pregnant and enrolled sometime between March 2012 and March 2015. Lung function assessments of children in the birth cohort were performed at 6 weeks, 1 year, and then annually until age 5 years. Eligible children had at least 1 valid lung function or anthropometric measurement or were assessed for wheezing through age 5 years.

The mother-child pairs were followed for a median of 7.8 years (interquartile range, 6.9-8.7). Of the children, 1054 had at least 1 lung function measurement, 1068 had at least 1 anthropometric measurement, and 954 were assessed longitudinally for wheezing up to 5 years.

During 7815 child-years of follow-up, 96 TB cases were reported (1228 cases per 100,000 person-years; 95% CI, 1006-1500); 43 (45%) cases occurred at less than 1 year of age, 20 (21%) at 1 to 2 years of age, and 33 (34%) after 2 years of age.

Among infants aged 1 to 5 years, lower length- and weight-for-age z scores at 6 weeks were associated with subsequent PTB (length-for-age regression coefficient, -0.59; 95% CI, -1.09 to -0.09; weight-for-age regression coefficient, -0.44; 95% CI, -0.87 to -0.01). Children who had TB before 1 year of age had statistically lower weight-for-age z-scores (-0.49; 95% CI, -0.82 to -0.16; P =.004) and body mass index (BMI) z-scores (-0.54; 95% CI, -0.83 to -0.25; P <.0001) at 5 years.

Children with PTB between ages 1 and 4 years had statistically lower length-for-age z-scores (-0.40; 95% CI, -0.68 to -0.11; P =.006) and weight-for-age z-scores (-0.30; 95% CI, -0.59 to -0.01; P =.042) but not BMI z-scores at 5 years.

Children with PTB before age 6 months had a greater than 2-fold risk of wheezing after 6 months (adjusted incidence rate ratio [IRR], 2.42; 95% CI, 1.32-4.43) vs those who did not have PTB. The risk of subsequent wheezing also was increased when PTB developed before age 12 months (adjusted IRR, 1.64; 95% CI, 1.04-2.60), 24 months (adjusted IRR, 1.69; 95% CI, 1.05-2.72), or 36 months (adjusted IRR, 2.07; 95% CI, 1.03-4.17).

Children with PTB had lower time to peak tidal expiratory flow over total expiratory time (t_PTEF/t_E) (-2.35%; 95% CI, -4.86 to -0.17; P =.048) at 5 years and increased exhaled nitric oxide (2.88; 95% CI, 0.57 to 5.19; P =.025) at 2 years, based on a multivariable mixed-effects linear model that limited follow-up for TB before age 1 year. Children with TB at ages 1 to 4 years had impaired tidal volume (-9.32 mL; 95% CI, -14.89 to -3.75) and t_PTEF/t_E (-2.35%; 95% CI, -4.86 to -0.17) at age 5 years.

Among several limitations, the findings may be less relevant to communities with low TB prevalence, and markers of environmental carbon fuel or air pollution were not included in the multivariable model. Also, the analysis of microbiologically confirmed TB was potentially underpowered.

“These results suggest that prevention of tuberculosis disease in the first few years of life may have substantial long-term benefits through childhood,” concluded the study authors.

This article originally appeared on Pulmonology Advisor