Aerobic fitness and physical activity levels of children born prematurely following randomization to postnatal dexamethasone

Abstract

Objective: To investigate the effects of postnatal dexamethasone treatment on aerobic fitness and physical activity levels in school-aged children born with very low birth weight (VLBW).

Study design: This was a follow-up study of 65 VLBW infants who participated in a randomized controlled trial of dexamethasone (DEX) to reduce ventilator dependency. Aerobic fitness was determined from peak oxygen uptake (VO(2peak)) with a cycle ergometer. Habitual physical activity was assessed by questionnaire.

Results: A trend for a treatment with an interaction between treatment and of diagnosis of chronic lung disease (CLD) was found, with the children in the placebo group with CLD having the lowest VO(2peak) (P = .09). Reduced fitness was seen in 53% of the group treated with DEX and 48% of the group given placebo. No between-group differences in physical activity were seen. Parental reports suggested that nearly two-thirds of the children participated in < 1 hour per week of vigorous physical activity, which was explained in part by decreased large airway function (r = 0.30; P = .03).

Conclusions: We found no adverse effect of postnatal DEX on aerobic fitness or habitual physical activity at school age. However, the reduced fitness and physical activity levels emphasize the need for closer follow-up and early interventions promoting physical activity to reduce the risk of chronic disease in this at-risk population.

Figure 1

Follow-up details of postnatal randomized controlled trial of DEX.

Figure 2

Boxplots showing aerobic fitness for treatments groups by CLD status. There was a trend (p=0.09) for an interaction with the participants who received Placebo and had CLD having the lowest fitness.