Pubertal origin of growth retardation in inborn errors of protein metabolism: A longitudinal cohort study.

OBJECTIVES: Inherited amino-acid metabolism disorders (IAAMDs) require lifelong protein-restricted diet. We aimed to investigate: 1/ whether IAAMDs was associated with growth, pubertal, bone mineral apparent density (BMAD) or body composition impairments; 2/ associations linking height, amino-acid mixture (AAM), plasma amino-acids and IGF1 concentrations. DESIGN: Retrospective longitudinal study of 213 patients with neonatal-onset urea cycle disorders (UCD,n = 77), organic aciduria (OA,n = 89), maple syrup urine disease (MSUD,n = 34), or tyrosinaemia type 1 (n = 13). METHODS: We collected growth parameters, pubertal status, BMAD, body composition, protein-intake, and IGF1 throughout growth. RESULTS: Overall final height (n = 69) was below target height (TH): -0.9(1.4) vs. -0.1(0.9) SD, p < 0.001. Final height was ≤ TH-2SD in 12 (21%) patients. Height ≤ - 2SD was more frequent during puberty than during early-infancy and pre-puberty: 23.5% vs. 6.9%, p = 0.002; and vs. 10.7%, p < 0.001. Pubertal delay was frequent (26.7%). Height (SD) was positively associated with isoleucine concentration: ß, 0.008; 95%CI, 0.003 to 0.012; p = 0.001. In the pubertal subgroup, height (SD) was lower in patients with vs. without AAM supplementation: -1.22 (1.40) vs. -0.63 (1.46) (p = 0.02). In OA, height and median (IQR) isoleucine and valine concentrations(µmol/L) during puberty were lower in patients with vs. without AAM supplementation: -1.75 (1.30) vs. -0.33 (1.55) SD, p < 0.001; and 40 (23) vs. 60 (25) (p = 0.02) and 138 (92) vs. 191 (63) (p = 0.01), respectively. No correlation was found with IGF1. Lean-mass index was lower than fat-mass index: -2.03 (1.15) vs. -0.44 (0.89), p < 0.001. CONCLUSIONS: In IAAMDs, growth retardation worsened during puberty which was delayed in all disease subgroups. Height seems linked to the disease, AAM composition and lower isoleucine concentration, independently of the GH-IGF1 pathway. We recommend close monitoring of diet during puberty.

Resistance Training and Protein Supplementation Increase Strength After Bariatric Surgery: A Randomized Controlled Trial.

OBJECTIVE: Physical activity and dietary regimens to optimize health outcomes after bariatric surgery are not well known. This study aimed to determine whether resistance training with dietary protein supplementation is effective in maintaining body composition and physical fitness after obesity surgery. METHODS: Seventy-six women with obesity undergoing Roux-en-Y gastric bypass were randomly assigned at the time of surgery to receive either usual care (controls [CON], n = 22), usual care and additional (whey) protein intake (PRO, n = 31), or usual care, additional protein intake, and supervised strength training for 18 weeks (PRO+EX, n = 23). The primary outcome was pre- to 6-month postsurgery change in lean body mass (by dual-energy x-ray absorptiometry). Secondary outcomes included changes in muscle strength (by one-repetition maximum testing). RESULTS: Loss over time in lean body mass did not differ between groups (CON: mean,-8.8 kg; 95% CI: -10.1 to -7.5 kg; PRO: mean, -8.2 kg; 95% CI: -9.3 to -7.1 kg; PRO+EX: mean, -7.7 kg; 95% CI: -9.0 to -6.5 kg; P = 0.899). The increase in relative lower-limb muscle strength was higher in the PRO+EX group (+0.6 [0.3 to 0.8]) versus +0.1 (-0.1 to 0.4) and +0.2 (0.0 to 0.4) kg/kg body mass in CON and PRO groups, respectively (P = 0.021). CONCLUSIONS: Loss in muscle strength observed after bariatric surgery can be overcome by resistance training with additional protein intake.