Fat Mass, Physical Fitness, and Cardiovascular Risk in Children

The maintenance of a healthy fat mass may improve cardiovascular health in childhood according to findings published in Scientific Reports.

Globally, more than 100 million children have obesity and over 200 million children are overweight. Physical fitness and body composition are closely related to each other. A more favorable cardiovascular disease (CVD) risk profile in children has been associated with physical fitness and cardiorespiratory fitness; however, the association of physical fitness may or may not be influenced by accounting for accurately measured body composition, and the association of body composition may or may not be influenced by accounting for physical fitness. Researchers sought to investigate the independent associations of physical fitness and body composition with risk factors for CVD in children.

To accomplish this, researchers conducted a cross-sectional study that included 411 children (200 girls, 211 boys) from the general population of Östergötland, Sweden. The participants were aged 9.5±0.1 years, and their data were from the SPINACH (Studies of Prospective Health Determinants in Infancy and Childhood) study that was conducted between 2016 and 2020. This study included measures of body composition, physical fitness, and health outcomes. Some participants provided a blood sample for analyses of CVD risk factors (175, comparable with the other 236 children [average BMI {17.0 vs 16.9}, age {9.6 vs. 9.5 years}, sex distribution {55.1% vs. 46.6% boys}, and maternal educational attainment {80.5% vs. 75.0% university degree}]).

Body composition and physical fitness were strongly associated, emphasizing the need for mutual adjustments when investigating their independent associations with CVD risk factors.  BMI, % fat mass, and fat mass index were all positively associated with systolic and diastolic blood pressure, homeostatic model assessment of insulin resistance (HOMA-IR) and metabolic syndrome score (all β≥0.229; P ≤.001), utilizing unadjusted linear regression analyses. Adjustments for covariates (age, sex, maternal educational level, maternal BMI), fat-free mass, and physical fitness did not affect these associations. Fat-free mass had weak associations with CVD risk factors and no statistically significant associations after adjustments (all P >.27). Greater motor fitness and cardiorespiratory fitness were associated with lower HOMA-IR and metabolic syndrome score (all β≤-0.158; P ≤.039) until adjustments for covariates and body composition when no significant association was measured.

Study limitations that were noted include the cross-sectional design, the high proportion of mothers with a university degree, and the lack of data regarding pubertal status.

Researchers concluded, after adjustments for covariates and physical fitness, that greater BMI and fat mass is associated with CVD risk factors. “[A]ssociations with BMI were generally as strong as with accurately measured fat mass which may have implication given the easy measurement of BMI in children,” the researchers wrote. “However, fat-free mass did not have any beneficial associations with CVD risk factors which support the notion that the focus for cardiovascular health promotion during childhood could be on excess fat mass and not on the fat-free mass.”

Reference

Henriksson P, Sandborg J, Henström M, et al. Body composition, physical fitness and cardiovascular risk factors in 9-year-old children. Sci Rep. Published online February 17, 2022. doi:10.1038/s41598-022-06578-w