Hair Minerals and Metabolic Health in Belgian Elementary School Girls

Literature has repeatedly shown a relationship between hair minerals and metabolic health, although studies in children are currently lacking. This study aims to investigate hair levels of calcium (Ca), copper (Cu), magnesium (Mg), iron (Fe), phosphorus (P), and zinc (Zn) and their association with (1) overweight/obesity and (2) metabolic health in Flemish elementary school girls between 5 and 10 years old. Two hundred eighteen girls participated in this study as part of the baseline ChiBS project. Children were subjected to physical examinations, blood and hair sampling. Hair minerals were quantitatively determined via inductively coupled plasma–mass spectrometry after microwave-assisted acid digestion. Body mass index (BMI) and body fat percentage (BF%) were studied as anthropometric parameters, and a metabolic score (including systolic and diastolic blood pressure, insulin resistance and non-high-density lipoprotein (non-HDL) cholesterol as parameters) was calculated, with higher scores indicating a more unhealthy metabolic profile. Hair Ca, Ca/Mg, and Ca/P positively correlated with the anthropometric parameters. An inverse correlation was observed between Ca, Mg, and Ca/P in hair and the metabolic score. Inverse correlations were also observed for individual metabolic parameters (i.e., diastolic blood pressure, homeostasis model assessment for insulin resistance, non-HDL cholesterol). In particular, girls with a total number of three or more metabolic parameters above the age-specific 75th percentile showed significantly reduced hair Ca, Mg, and Ca/P concentrations. This study showed reduced hair mineral concentrations in young girls with a more unhealthy metabolic profile. Positive associations were observed between some minerals and BMI and BF%.     

Physical Activity and Physical Fitness in African-American Girls With and Without Obesity

WARD, DIANNE S, STEWART G TROST, GWEN FELTON, RUTH SAUNDERS, MARY ANN PARSONS, MARSHA DOWDA, RUSSELL R PATE. Physical activity and physical fitness in African-American girls with and without obesity. Lack of physical activity and low levels of physical fitness are thought to be contributing factors to the high prevalence of obesity in African-American girls. To examine this hypothesis, we compared habitual physical activity and physical fitness in 54 African-American girls with obesity and 96 African-American girls without obesity residing in rural South Carolina. Participation in vigorous (6 METs) (VPA) or moderate and vigorous physical activity (4 METs) (MVPA) was assessed on three consecutive days using the Previous Day Physical Activity Recall. Cardiorespiratory fitness was assessed using the PWC 170 cycle ergometer test. Upper body strength was determined at two sites via isometric cable tensiometer tests. Relative to their counterparts without obesity, girls with obesity reported significantly fewer 30-minute blocks of VPA (0. 90 ± 0. 14 vs. 1. 3 ± 0. 14) and MVPA (1. 2 ± 0. 18 vs. 1. 7 ± 0. 16) (p<0. 01). Within the entire sample, VPA and MVPA were inversely associated with body mass index (r=?0. 17 and r=?0. 19) and triceps skinfold thickness (r=?0. 19 and r=?0. 22) (p<0. 05). In the PWC 170 test and isometric strength tests, girls with obesity demonstrated absolute scores that were similar to, or greater than, those of girls without obesity; however, when scores were expressed relative to bodyweight, girls with obesity demonstrated significantly lower values (p<0. 05). The results support the hypothesis that lack of physical activity and low physical fitness are important contributing factors in the development and/or maintenance of obesity in African-American girls.     

Cross-Sectional Relationship Between Chronic Stress and Mineral Concentrations in Hair of Elementary School Girls

Chronic stress exposure is associated with diverse negative health outcomes. It has been hypothesised that stress may also negatively affect the body's mineral status. This study investigates the association between chronic stress and long-term mineral concentrations of calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), phosphorus (P) and zinc (Zn) in scalp hair among elementary school girls. Complete information on child-reported stress estimates (Coddington Life Events Scale (CLES)), hair cortisone and hair mineral concentrations, and predefined confounders in the stress–mineral relationship (i.e. age, body mass index, physical activity, diet, hair colour and parental education) was provided cross-sectionally for 140 girls (5–10 years old). The relationship between childhood stress measures (predictor) and hair minerals (outcome) was studied using linear regression analysis, adjusted for the abovementioned confounders. Hair cortisone concentrations were inversely associated with hair mineral concentrations of Ca, Mg, Zn and the Ca/P ratio. Children at risk by life events (CLES) presented an elevated Ca/Mg ratio. These findings were persistent after adjustment for confounders. This study demonstrated an independent association between chronic stress measures and hair mineral levels in young girls, indicating the importance of physiological stress–mineral pathways independently from individual or behavioural factors. Findings need to be confirmed in a more heterogeneous population and on longitudinal basis. The precise mechanisms by which stress alters hair mineral levels should be further elucidated.     

Fatness and Physical Fitness of Girls 7 to 17 Years

A two-fold approach was used to investigate the association between fatness and fitness of girls 7 to 17 years of age: first, age-specific correlations between fatness and measures of health-related and motor fitness, and second, comparisons of fitness levels of girls classified as fat and lean. A representative sample of 6700 between 7 to 17 years was surveyed. Adiposity (fatness) was estimated as the sum of five skinfolds (biceps, triceps, subscapular, suprailiac, medial calf). Physical fitness included health-related items (step test, PWC₁₇₀ the sit and reach, sit-ups and leg lifts, flexed arm hang) and motor performance items (standing long jump, vertical jump, arm pull strength, flamingo stand, shuttle run, plate tapping). Age-specific partial correlations between fatness and each fitness item, controlling for stature and weight, were calculated. In addition, in each age group the fattest 5% (presumably the obese) and the leanest 5% were compared on each fitness test. After controlling for stature and weight, subcutaneous fatness accounts for variable percentages of the variance in each fitness item. Estimates for health-related fitness items are: cardiorespiratory endurance - step test (3% to 5%) and PWC₁₇₀ (0% to 16%), flexibility - sit and reach (3% to 8%), functional strength - flexed arm hang (6% to 17%) and abdominal strength - sit-ups/leg lifts (1% to 8%). Corresponding estimates for motor fitness items are more variable: speed of limb movement -plate tapping (0% to 3%), balance - flamingo stand (0% to 5%), speed and agility - shuttle run (2% to 12 %), static strength - arm pull (4% to 12%), explosive strength - standing long jump/vertical jump (11% to 18%). At the extremes, the fattest girls have generally poorer levels of health-related and motor fitness.