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Background/Objectives The strong regulation of protein intake can lead to overconsumption of total energy on diets with a low proportion of energy from protein, a process referred to as protein leverage. The protein leverage hypothesis posits that protein leverage explains variation in energy intake and potentially obesity in ecological settings. Here, we tested for protein leverage and the protein leverage hypothesis in children and adolescents. Subjects/Methods A population sample of children, mean (SD) age 7.6 (0.4) years (n = 422), followed up at age 9.8 (0.4) years (n = 387) and at age 15.8 (0.4) years (n = 229), participating for the Physical Activity and Nutrition in Children (PANIC) study. Exposures: 4-day food records-related proportional energy intake of proteins, fats, and carbohydrates. Outcomes: energy intake, body mass index (BMI) z-score and dual-energy X-ray absorptiometry-related energy expenditure. Results Proportional energy intake of proteins was inversely associated with energy intake following power functions at all 3 ages (mean [95%CI] strength of leverage of L = −0.36 [−0.47 to −0.25]; L = −0.26 [−0.37 to −0.15]; L = −0.25 [−0.38 to −0.13]; all P < 0.001). Mixture analysis indicated that variance in energy intake was associated primarily with the proportional intake of energy from proteins, not with either fats or carbohydrates. At all 3 ages, energy intake was not associated with BMI z-score but positively associated with energy expenditure (all P < 0.001). Conclusions This study provides evidence consistent with protein leverage in a population sample of children and adolescents. Increased energy intake on diets with lower protein content was counterbalanced by increased energy expenditure and therefore did not translate into increased adiposity. Introduction, Background/Objectives: The strong regulation of protein intake can lead to overconsumption of total energy on diets with a low proportion of energy from protein, a process referred to as protein leverage. The protein leverage hypothesis posits that protein leverage explains variation in energy intake and potentially obesity in ecological settings. Here, we tested for protein leverage and the protein leverage hypothesis in children and adolescents. Subjects/Methods: A population sample of children, mean (SD) age 7.6 (0.4) years (n = 422), followed up at age 9.8 (0.4) years (n = 387) and at age 15.8 (0.4) years (n = 229), participating for the Physical Activity and Nutrition in Children (PANIC) study. Exposures: 4-day food records-related proportional energy intake of proteins, fats, and carbohydrates. Outcomes: energy intake, body mass index (BMI) z-score and dual-energy X-ray absorptiometry-related energy expenditure. Results: Proportional energy intake of proteins was inversely associated with energy intake following power functions at all 3 ages (mean [95%CI] strength of leverage of L = −0.36 [−0.47 to −0.25]; L = −0.26 [−0.37 to −0.15]; L = −0.25 [−0.38 to −0.13]; all P < 0.001). Mixture analysis indicated that variance in energy intake was associated primarily with the proportional intake of energy from proteins, not with either fats or carbohydrates. At all 3 ages, energy intake was not associated with BMI z-score but positively associated with energy expenditure (all P < 0.001). Conclusions: This study provides evidence consistent with protein leverage in a population sample of children and adolescents. Increased energy intake on diets with lower protein content was counterbalanced by increased energy expenditure and therefore did not translate into increased adiposity.

Modeling of retrospectively collected multi-center data of a rare disease in pediatrics is challenging because laboratory data can stem from several decades measured with different assays. Here we present a retrospective pharmacometrics (PMX) based data analysis of the rare disease congenital hypothyroidism (CH) in newborns and infants. Our overall aim is to develop a model that can be applied to optimize dosing in this pediatric patient population since suboptimal treatment of CH during the first 2 years of life is associated with a reduced intelligence quotient between 10 and 14 years. The first goal is to describe a retrospectively collected dataset consisting of 61 newborns and infants with CH up to 2 years of age. Overall, 505 measurements of free thyroxine (FT4) and 510 measurements of thyrotropin or thyroid-stimulating hormone were available from patients receiving substitution treatment with levothyroxine (LT4). The second goal is to introduce a scale/location-scale normalization method to merge available FT4 measurements since 34 different postnatal age- and assay-specific laboratory reference ranges were applied. This method takes into account the change of the distribution of FT4 values over time, i.e. a transformation from right-skewed towards normality during LT4 treatment. The third goal is to develop a practical and useful PMX model for LT4 treatment to characterize FT4 measurements, which is applicable within a clinical setting. In summary, a time-dependent normalization method and a practical PMX model are presented. Since there is no on-going or planned development of new pharmacological approaches for CH, PMX based modeling and simulation can be leveraged to personalize dosing with the goal to enhance longer-term neurological outcome in children with the rare disease CH.

Compound heterozygous and homozygous (comp/hom) mutations in solute carrier family 34, member 3 (SLC34A3), the gene encoding the sodium (Na+)-dependent phosphate cotransporter 2c (NPT2c), cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH), a disorder characterized by renal phosphate wasting resulting in hypophosphatemia, correspondingly elevated 1,25(OH)(2) vitamin D levels, hypercalciuria, and rickets/osteomalacia. Similar, albeit less severe, biochemical changes are observed in heterozygous (het) carriers and indistinguishable from those changes encountered in idiopathic hypercalciuria (IH). Here, we report a review of clinical and laboratory records of 133 individuals from 27 kindreds, including 5 previously unreported HHRH kindreds and two cases with IH, in which known and novel SLC34A3 mutations (c.1357delTTC [p.F453del]; c.G1369A [p.G457S]; c.367delC) were identified. Individuals with mutations affecting both SLC34A3 alleles had a significantly increased risk of kidney stone formation or medullary nephrocalcinosis, namely 46% compared with 6% observed in healthy family members carrying only the wild-type SLC34A3 allele (P=0.005) or 5.64% in the general population (P<0.001). Renal calcifications were also more frequent in het carriers (16%; P=0.003 compared with the general population) and were more likely to occur in comp/hom and het individuals with decreased serum phosphate (odds ratio [OR], 0.75, 95% confidence interval [95% CI], 0.59 to 0.96; P=0.02), decreased tubular reabsorption of phosphate (OR, 0.41; 95% CI, 0.23 to 0.72; P=0.002), and increased serum 1,25(OH)(2) vitamin D (OR, 1.22; 95% CI, 1.05 to 1.41; P=0.008). Additional studies are needed to determine whether these biochemical parameters are independent of genotype and can guide therapy to prevent nephrocalcinosis, nephrolithiasis, and potentially, CKD.

In El viento de la Luna (The Wind of the Moon) Antonio Muñoz Molina returns to the imaginary world of Mágina, a place where Nature plays a determinant role. Our ecocritic lecture is focussing on the relation between mankind and environment., En El viento de la Luna Antonio Muñoz Molina regresa al mundo imaginario de Mágina, espacio en el que la Naturaleza desempeña un papel determinante. Nuestra lectura ecocrítica sitúa en un primer plano la relación entre el hombre y el medio ambiente.