Antenatal Steroid Exposure, Aerobic Fitness, and Physical Activity in Adolescents Born Preterm with Very Low Birth Weight

Risk of Obesity and Unhealthy Central Adiposity in Adolescents Born Preterm With Very Low Birthweight Compared to Term-Born Peers

Background: Early-life factors such as preterm birth or very low birthweight (VLBW) are associated with increased cardiovascular disease risk. However, it remains unknown whether this is due to an increased risk of obesity (unhealthy central adiposity) because studies have predominantly defined obesity based on BMI, an imprecise adiposity measure. Objective: Investigate if adolescents born preterm with VLBW have a higher risk of unhealthy central adiposity compared to term-born peers. Study Design: Cross-sectional analysis of data from a prospective cohort study of 177 individuals born preterm with VLBW (<1500 g) and 51 term-born peers (birthweight ≥2500 g). Individuals with congenital anomalies, genetic syndromes, or major health conditions were excluded. Height, weight, waist circumference, skin fold thickness, and dual energy X-ray absorptiometry body composition were measured at age 14 years. We calculated BMI percentiles and defined overweight/obesity as BMI ≥85th percentile for age and sex. We estimated the preterm-term differences in overweight/obesity prevalence and adiposity distribution with multivariable generalized linear models. Results: There was no difference in small for gestational age status or overweight/obesity prevalence. Compared to term, youth born preterm with VLBW had lower BMI z-score [β -0.38, 95% confidence limits (CL) -0.75 to -0.02] but no differences in adiposity apart from subscapular-to-triceps ratio (STR; β 0.18, 95% CL 0.08 to 0.28). Conclusions: Adolescents born preterm with VLBW had smaller body size than their term-born peers and had no differences in central adiposity except greater STR.

Association of antenatal corticosteroids with kidney function in adolescents born preterm with very low birth weight

OBJECTIVE

Investigate if antenatal corticosteroids (ANCS) are associated with worse kidney function in adolescence and if greater adiposity magnifies this association.

STUDY DESIGN

Prospective cohort of 162 14-year-olds born preterm with very low birth weight (<1500 g). Outcomes were estimated glomerular filtration rate (eGFR) and first-morning urine albumin-to-creatinine ratio (UACR). We used adjusted generalized linear models, stratified by waist-to-height ratio (WHR) ≥ 0.5.

RESULTS

Fifty-five percent had ANCS exposure and 31.3% had WHR ≥ 0.5. In adjusted analyses of the entire cohort, ANCS was not significantly associated with eGFR or UACR. However, the ANCS-eGFR association was greater in those with WHR ≥ 0.5 (β -16.8 ml/min/1.73 m2, 95% CL -31.5 to -2.1) vs. WHR < 0.5: (β 13.9 ml/min/1.73 m2, 95% CL -0.4 to 28.1), interaction term p = 0.02.

CONCLUSION

ANCS exposure was not associated with worse kidney function in adolescence, though ANCS may be associated with lower eGFR if children develop obesity by adolescence.

Technical Update No. 439: Antenatal Corticosteroids at Late Preterm Gestation

OBJECTIVE

To update recommendations for administration of antenatal corticosteroids in the late preterm period.

TARGET POPULATION

Pregnant individuals at risk of preterm birth from 340 to 366 weeks gestation.

OPTIONS

Administration or non-administration of a single course of antenatal corticosteroids at 340 to 366 weeks gestation.

OUTCOMES

Neonatal morbidity (respiratory distress, hypoglycemia), long-term neurodevelopment, and other long-term outcomes (growth, cardiac/metabolic, respiratory).

BENEFITS, HARMS, AND COSTS

Administration of antenatal corticosteroids from 340 to 366 weeks gestation decreases the risk of neonatal respiratory distress but increases the risk of neonatal hypoglycemia. The long-term impacts of antenatal corticosteroid administration from 340 to 366 weeks gestation are uncertain.

EVIDENCE

For evidence on the neonatal effects of antenatal corticosteroid administration at late preterm gestation, we summarized evidence from the 2020 Cochrane review of antenatal corticosteroids and combined this with evidence from published randomized trials identified by searching Ovid MEDLINE from January 1, 2020, to May 11, 2022. Given the absence of direct evidence on the impact of late preterm antenatal corticosteroid administration on neurodevelopmental outcomes, we summarized evidence on the impact of antenatal corticosteroids across gestational ages on neurodevelopmental outcomes using the following sources: (1) the 2020 Cochrane review; and (2) evidence obtained by searching Ovid MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception to January 5, 2022. We did not apply date or language restrictions. Given the absence of direct evidence on the impact of late preterm antenatal corticosteroid administration on other long-term outcomes, we summarized evidence on the impact of antenatal corticosteroids across gestational ages on other long-term outcomes by combining findings from the 2020 Cochrane review with evidence obtained by searching Ovid MEDLINE for observational studies related to long-term cardiometabolic, respiratory, and growth effects of antenatal corticosteroids from inception to October 22, 2021. We reviewed reference lists of included studies and relevant systematic reviews for additional references. See Appendix A for search terms and summaries.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix B (Tables B1 for definitions and B2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

Maternity care providers, including midwives, family physicians, and obstetricians.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Grip strength is lower in adults born with extremely low birth weight compared to term-born controls

BACKGROUND

Grip strength predicts long-term morbidity and mortality in adults. We compared grip strength in adults born with extremely low birth weight (ELBW; under 1 kg) and a normal birth weight control group (NBW) and describe change in grip strength over a 10-year period in a longitudinal cohort study of preterm birth.

METHODS

Grip strength, body composition, and device-measured physical activity were assessed in 95 mature adults (MA) born ELBW (age 31.6 (1.6) mean (SD) years, 59 females) and 88 born NBW (age 31.9 (1.4) years, 52 females). Regression models were used to examine the effect of perinatal factors, body composition, physical activity, and physical self-efficacy on grip strength.

RESULTS

Grip strength was lower in MA born ELBW compared to NBW (31.8 (10.0) vs. 39.8 (11.2) kg; p < 0.001). Birth weight group was associated with grip strength independent of sex, height, and lean mass index, but device-measured physical activity was not. The change in grip strength from mid-20s to MA was similar in ELBW and NBW participants.

DISCUSSION

Grip strength in MA born ELBW is low and is similar to a reference group 25-30 years older, suggesting higher risk for cardiovascular and all-cause mortality.

IMPACT

Adults born extremely preterm have reduced grip strength compared to control participants born at full term. Reduced grip strength is a predictor of frailty and increased cardiovascular disease risk. Change in grip strength from age in mid-20s to mid-30s is similar in those born preterm and full-term-born controls. Grip strength is related to lean mass and not to device-measured physical activity-and correlates of grip strength are similar in those born preterm and term-born controls. Grip strength is a simple measure that may provide information about the health of adults born preterm.