BACKGROUND AND PURPOSE:

• Spirometric restriction (reduced FVC with a preserved FEV1/FVC ratio) is linked to increased risk of respiratory and non-respiratory conditions and all-cause mortality in adulthood
• Voraphani et al. (Lancet Respiratory Medicine, 2021) attempted to identify early-life risk factors for spirometric restriction in adult life

METHODS:

• Longitudinal, multicohort, population-based study
• Population
  • Healthy infants born between 1980 and 1984 from Tucson Children’s Respiratory Study (TCRS)
• Exposures
  • Lung function measured with spirometry at age 22, 26, 32, and 36 years
    • Normal: FEV1/FVC ≥10th percentile and FVC ≥10th percentile
    • Restrictive: FEV1/FVC ≥10th percentile and FVC <10th percentile
    • Obstructive: FEV1/FVC <10th percentile, independent of FVC

Note:

• Spirometry tests the forced expiratory volume of air that can be exhaled during forced breath
  • FEV1 (forced expiratory volume): Volume exhaled in the first second
  • FVC (forced vital capacity): Total volume exhaled after a deep breath

• Study design
  • Data collection questionnaires 
    • Answered by primary care giver at enrolment, child’s birth and through childhood and adulthood
    • Information included demographic features and parental health factors
  • Medical records
    • Birth measurement | Pregnancy data
  • Study nurses
    • Weight | Height | BMI
    • Collected from age 6 to 16 years
  • The associations between early-life risk factors and spirometric patterns were assessed by multivariate multinomial logistic regression analysis
    • Adjustment was for survey year, sex, and race–ethnicity
  • Replication testing for significant risk factors
    • Swedish Child (Barn), Allergy, Milieu, Stockholm, Epidemiological (BAMSE) | UK Manchester Asthma and Allergy Study (MAAS)
  • To generate a pooled estimate of the effect across cohorts, mixed-effect meta-analyses of relative risk ratios (rRR) from multinomial logistic regression models were performed

RESULTS:

• TCRS population: 652 participants | 1668 observations
• Independent predictors of spirometric restriction in adult life were
  • Maternal nutritional problems during pregnancy
    • rRR 2.48 (95% CI, 1.30 to 4.76); P=0.0062
  • Small for gestational age (birthweight <10th percentile)
    • rRR 3.26 (95% CI, 1.34 to 7.93); P=0.0093)
  • Underweight in childhood (BMI-for-age <5th percentile)
    • rRR 3.54 (95% CI, 1.35 to 9.26); P=0.010
• In the meta-analysis, there was persistence of association between spirometric restriction and
  • Small for gestational age: P=0.0028
  • Underweight in childhood: P<0.0001
• In the MAAS cohort, spirometric restriction was predicted by
  • Low BMI (<10th percentile) at age 11
    • rRR 3.66 (95% CI, 1.48 to 9.02); P=0.0048

CONCLUSION:

• Spirometric restriction in adulthood can be predicted by nutritional deficits during pregnancy, and poor growth in utero and in childhood
• The authors state

Poor growth and nutritional deficits in utero and throughout childhood precede and predict the development of spirometric restriction in adult life

Strategies to improve prenatal and childhood growth trajectories could help to prevent spirometric restriction and its associated morbidity and mortality burden

Learn More – Primary Sources:

The role of growth and nutrition in the early origins of spirometric restriction in adult life: a longitudinal, multicohort, population-based study

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