The restrictive spirometric pattern is defined as significantly reduced forced vital capacity (FVC) with preserved forced expiratory volume in one second (FEV1)/FVC ratio and is correlated with functional impairment, more comorbidities, and death in adulthood. However, there are limited data pertaining to its early origins. A study published online as part of the ATS 2020 International Conference assessed what early-life risk factors may be associated with spirometric restriction in adulthood.
The study collected data from the Tucson Children’s Respiratory Study (TCRS) population-based birth cohort. Pre-bronchodilator spirometry was performed at ages 22, 26, 32, and 36 years; results were stratified into three groups: normal (FEV1/FVC >10th percentile and FVC >10th percentile), obstructive (FEV1/FVC <10th percentile), and restrictive (FEV1/FVC >10th percentile and FVC <10th percentile). A total of 643 TCRS participants provided data on early-life factors, which were evaluated for their correlations with spirometry patterns later in life. Significant risk factors identified in the TCRS group were replicated in other groups, including BAMSE (n=1,650; lung function available at 24 years) and MAAS (n=411; lung function available at 18 years) cohorts; meta-analyses were conducted of all three groups.
In the TCRS group, patients whose mothers had prenatal nutritional problems (including anemia and excessive emesis) were twice as likely to have spirometric restriction in adulthood. Also in TCRS, an inverse association was observed between birthweight and adult spriometric restriction; this was also observed in the MAAS group. Meta-analyses observed that with every 100 g increase in birthweight, adulthood spirometric restriction risk was decreased by 4%. Across all three cohorts, patients who were underweight during childhood (body mass index [BMI] <5th percentile at any point between ages five and 16 years) were more than three times as likely to have restrictive spirometric pattern in adulthood versus those with normal weight. When assessed on a continuous scale, every one-unit increase in BMI at ages six to eight years lowered adult spirometric restriction risk by 22%.
“Poor nutritional status, in utero and throughout childhood, is associated with an increased risk for developing spirometric restriction in adult life. These findings support the role of prenatal/early-life factors as determinants of lung size and underscore the importance of optimal nutritional status early in life for the prevention of spirometric restriction,” the researchers concluded.