MON-219 - Characterization of Body Composition and Lipids in Youth with Turner Syndrome

Body composition and lipid metabolism have been reported altered in individuals with Turner Syndrome (TS) when compared to the general population. Short stature in TS may complicate the interpretation of body composition assessed by dual energy X-ray absorptiometry (DXA). We aimed to characterize the body composition and lipids of youth with TS and investigate their relationships with body size, genotype and estrogen and growth hormone therapy.

Clinical data from children ≥ 9 years with TS and menarche with ≥1 DXA completed were abstracted into REDCap and analyzed with Stata. DXA body composition outcomes included total (TLSTM) and appendicular (ALSTM) lean soft tissue mass and fat mass (FM) reported in kg and indexed to height (kg/m2, LSTMI, ALSTMI, FMI). Z-scores for age and sex were determined using Bone Mineral Density and Child Study reference data and adjusted for height Z-score (HAZ). Data were summarized using standard descriptive statistics and reported as mean±SD or non-parametric equivalent. Group differences were assessed by t- tests or non-parametric equivalent; correlations by Spearman’s rho(rs), expressed as (n), rho, p.

92 individuals, aged 14-33 yrs (median 18.5 yr), were included with a mean HAZ -2.14±1.19 and BMI-Z score 0.81±0.88. The mean age of menarche was 14.2±1.8 yr; 20 (21.7%) spontaneous, the remainder required estradiol induction. DXA was performed 2.5±1.7 yrs following menarche, mean age 16.5±1.7 yr. Mean TLSTM-Z and ALSTM-Z were -2.07±1.13 (p < 0.001, vs reference data) and -2.21±1.04 (p < 0.001). Mean FM-Z was 0.74 ± 1.01 (p < 0.001). Following HAZ adjustment, these increased to -0.76 ± 1.01 (p < 0.001), -1.02±0.94 (p < 0.001), and 0.89 ± 1.00 (p < 0.001). Positive correlation was found between LDL-C, non-HDL-C and FM-Z before (rs(47)=0.31,p=0.04; rs(47)=0.32,p=0.03) and after HAZ adjustment (rs(47)=0.28,p=0.06; rs(47)=0.30,p=0.04). Negative correlation was found between HDL-C and FM-Z before (rs(47)=-0.60,p < 0.001) and after HAZ adjustment (rs(47)=-0.58,p < 0.001). The proportion of patients with low TLSTM-Z (Z-score <-2) decreased from 48.7% to 9.2% (p < 0.001) and ALSTM-Z from 55% to 15% (p < 0.001) after HAZ adjustment. These were similar if LSTM indices were used, with 14.5% and 26.7% respectively. There were no differences in LSTM or LSTM index Z-scores between patients receiving estradiol or growth hormone. There was a downward trend in LDL-C and non-HDL-C for patients treated with growth hormone (p = 0.06, p=0.07).

Overall, DXA showed deficits in lean body mass with excess fat mass in youth with TS regardless of induced versus spontaneous menarche. The magnitude of the deficits was attenuated after height adjustment; however, these differences persisted when compared to the reference population. Fat mass continued to have a significant positive correlation with non-HDL-C and negative correlation with HDL-C following HAZ adjustment.

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