Insulin resistance has been found to start to rise from about age 7, and increase into puberty.
Insulin resistance is known to be higher during puberty in both sexes, but the time frame of the onset of this was not known. This study was done to look at that, and showed the rise in insulin resistance did not start with the start of puberty, but at about age 7.
“Age Before Stage: Insulin Resistance Rises Before the Onset of Puberty” LINK
The link is to the full text, with tables to show the info more clearly. Here are some quotes. I know it is “a bit” dense, but some people love the details.
“The IR of early adolescence is usually attributed to puberty, but our data suggest that it emerges well before the rise in LH that initiates puberty and before any discernible physical changes. The prepubertal increase in IR was partially accounted for by increases in adiposity, with percent fat alone explaining 25 and 30% of the variation in IR in boys and girls, respectively. Type 2 diabetes is increasingly common in childhood, and the majority of diabetic children are female (23), consistent with their greater adiposity and IR. However, even when accounting for increases in percent fat, IGF-1, and age, over half of the total variance in IR remained unexplained (model 6).
We are unsure why insulin demand should begin to rise from as early as 7 years, although three observations are noteworthy. First, adiposity starts to rise around the same age, and fat is known to reduce insulin action. Second, serum IGF-1 rises progressively as puberty approaches, and the growth hormone/IGF axis is known to be associated with IR (24). In the current study, IGF-1 contributed an additional 3% to the variance of IR in both sexes, after accounting for the effects of adiposity and age. The higher IGF-1 levels in girls may relate to their greater adiposity, or may reflect the fact that low levels of estrogen produced prepubertally in girls could have a sensitizing effect on growth hormone, thereby increasing both IGF-1 and IR. Alternatively, since both insulin and IGF-1 belong to the same proinsulin superfamily, girls could be more “IGF-1 resistant” in the same way that they are more insulin resistant.
Third, adrenarche occurs around 6–8 years. Adrenarche precedes activation of the gonadal axis and is characterized by an abrupt rise in the adrenal androgen dehydroepiandrosterone (25). Although speculative, it is possible that dehydroepiandrosterone (sulfate) is responsible for the age-dependent rise in IR either directly or indirectly by promoting fat accumulation. Adrenarche has been linked before to IR in girls (3), though not in boys (26).”
“In summary, IR is already rising from 7 years of age in contemporary boys and girls, ∼3–4 years before pubertal onset, however it is defined. The rise can partly be explained by the accumulation of fat, and to a lesser extent by rising IGF-1. There remains an age-related, but unexplained, residual that might be ascribed to the rise in adrenal hormones. The demography of childhood diabetes is changing, and prepubertal IR may be important.”
Diabetes Care. 2012 Mar; 35(3): 536–541. doi: 10.2337/dc11-1281
Age Before Stage: Insulin Resistance Rises Before the Onset of Puberty
A 9-year longitudinal study (EarlyBird 26)
Alison N. Jeffery, PHD, Brad S. Metcalf, MSC, Joanne Hosking, PHD, Adam J. Streeter, MSC, Linda D. Voss, PHD, and Terence J. Wilkin, MD