219 - Body composition in adults born preterm with very low birth weight; mid-adulthood outcomes from a two-country birth cohort study

Adults born preterm with very low birth weight (VLBW; < 1500g) are shorter and have increased levels of cardiometabolic risk factors than those born at term. Studies in young adulthood have suggested lower lean body mass, but body composition trajectories to later adulthood have not been studied. 

Objective: To investigate body size and composition in VLBW adults compared to term born controls measured by anthropometry and 8-polar bioelectrical impedance analysis. We hypothesized that adults born preterm with VLBW have lower lean body mass and higher fat percentage than those born at term and that their fat percentage show a higher relative increase since the young adulthood assessment.

Design/Methods:

We studied two birth cohorts with harmonized methods, the Helsinki Study of Very Low Birth Weight Adults (HeSVA) and the Norwegian University of Science and Technology (NTNU) Low Birth Weight Life cohort study. HeSVA participants were born in 1978-1985, control participant group-matched for sex, age and birth hospital. NTNU participants were born in 1986-1988 and control participant-group comprised term born infants non-small for gestational age (>37 weeks of gestation, >=10^th percentile adjusted for gestational age, sex, and parity). The 2019-2021 mid-adulthood assessment was attended by 137 VLBW (92 HeSVA/45 NTNU) and 158 (90 HeSVA/68 NTNU) control participants. Body size and composition was assessed by anthropometry and 8-polar bioelectrical impedance analysis (Seca® mBCA 515) in 114 VLBW and 143 controls and the results were compared with former body composition results measured in young adulthood by DXA. We analysed data by linear regression and mixed models.

Results: Adjusted for age and cohort, mid-adulthood body size and body composition differed between the VLBW and control group (Table 1). VLBW men were 6.4 cm (3.6 to 8.5) and women 4.2 cm (1.5 to 6.4) shorter and their head circumference was smaller than term controls. There was no difference in fat percentage and body mass index. VLBW women and men had lower lean body mass than controls, but this was attributable to their shorter height. There was no significant age interaction between young and mid-adulthood body composition (VLBW*young vs mid-adulthood p >0.2).

Conclusion(s):

In mid-adulthood, VLBW adults had lower lean body mass which was largely explained by their shorter height. While the participants put on weight between young and adulthood, differences in body composition between VLBW and term groups remained largely similar as in young adulthood.