Physical activity attenuates the mid-adolescent peak in insulin resistance but by late adolescence the effect is lost: a longitudinal study with annual measures from 9–16 years (EarlyBird 66)

Abstract

Aims/hypothesis The aim of this work was to test whether the mid-adolescent peak in insulin resistance (IR) and trends in other metabolic markers are influenced by long-term exposure to physical activity. Methods Physical activity (7 day ActiGraph accelerometry), HOMA-IR and other metabolic markers (glucose, fasting insulin, HbA 1c , lipids and BP) were measured annually from age 9 years to 16 years in 300 children (151 boys) from the EarlyBird study in Plymouth, UK. The activity level of each child was characterised, with 95% reliability, by averaging their eight annual physical activity measures. Age-related trends in IR and metabolic health were analysed by multilevel modelling, with physical activity as the exposure measure (categorical and continuous) and body fat percentage (assessed by dual-energy X-ray absorptiometry) and pubertal status (according to age at peak height velocity and Tanner stage) as covariates. Results The peak in IR at age 12-13 years was 17% lower (p<0.001) in the more active adolescents independently of body fat percentage and pubertal status. However, this difference diminished progressively over the next 3 years and had disappeared completely by the age of 16 years (e.g. difference was −14% at 14 years, −8% at 15 years and +1% at 16 years; 'physical activity×age 2 ' interaction, p<0.01). Triacylglycerol levels in girls (−9.7%, p=0.05) and diastolic blood pressure in boys (−1.20 mmHg, p=0.03) tended to be lower throughout adolescence in the more active group. Conclusions/interpretation Our finding that physical activity attenuates IR during mid-adolescence may be clinically important. It remains to be established whether the temporary attenuation in IR during this period has implications for the development of diabetes in adolescence and for future metabolic health generally.

Insulin resistance is higher in prepubertal girls but switches to become higher in boys at age 16: A Cohort Study (EarlyBird 57)

“…We have previously shown that physical activity attenuates the mid‐adolescent peak in IR and that this effect disappears by 16 years, independent of adiposity and pubertal stage . In our final model, however, physical activity explained only a small proportion of the gender difference in IR.…”

“…Children's MVPA varied little from 9 to 16 years, and in order to characterize the overall long‐term physical activity level of each child, their MVPA was averaged across all 8 time points. In doing so, the children were ranked according to their activity levels throughout the whole period with 95% reliability, compared with 70% reliability when using 1 annual measure of physical activity …”

The prospective association between objectively measured sedentary time, moderate‐to‐vigorous physical activity and cardiometabolic risk factors in youth: a systematic review and meta‐analysis

“…In a follow‐up from ages 9 to 16, children in the more active groups (boys: ≥50 min MVPA per day, girls: ≥35 min MVPA per day) attenuated the mid‐adolescent peak in HOMA‐IR compared with the less active group, independent of body fat percentage and pubertal status . However, at age 16, there were no differences between the activity groups . Similarly, an Estonian study ( n = 120) found no association between MVPA and HOMA‐IR in boys .…”

“…The EarlyBird cohort found that number of minutes spent ≥3 METs were associated with lower mean arterial BP in boys from ages 5 to 8 . From the same cohort, diastolic BP (DBP) were marginally lower in active boys (≥50 min MVPA per day) when compared with those that were less active throughout adolescence (ages 9 to 16) . Similarly, one study observed a favourable but non‐significant effect on SBP in the intervention group between baseline and post‐intervention .…”

Effects of 6-Weeks High-Intensity Interval Training in Schoolchildren with Insulin Resistance: Influence of Biological Maturation on Metabolic, Body Composition, Cardiovascular and Performance Non-responses

“…However, despite of insulin resistance increases with age, racial health disparities and pubertal status (Ball et al, 2006), some authors have shown in girls and boys from 9 to 16 years an interesting relationship between physical activity and decreases in both insulin and the homeostasis model assessment of insulin resistance (HOMA-IR) marker changes throughout development (Metcalf et al, 2015). …”