The association between newborn screening analytes as measured on a second screen and childhood autism in a Texas Medicaid population.

Autism (or autism spectrum disorder [ASD]) is an often disabling childhood neurologic condition of mostly unknown cause. We previously explored whether there was an association of ASD with any analyte measured in the first newborn screening blood test. Here we explore the second screen. Our matched case-control study examined data on 3-5 year-old patients with any ASD diagnosis in the Texas Medicaid system in 2010-2012. Subjects were linked to their 2007-2009 newborn screening blood test data, which included values for 36 analytes or analyte ratios. Data were available for 3,005 cases and 6,212 controls. The most compelling associations were evident for fatty acid oxidation analytes octanoylcarnitine (C8) and octanoylcarnitine/acetylcarnitine (C8/C2). Their adjusted odds ratios comparing 10th versus first analyte deciles were between 1.42 and 1.54 in total births, term births, and males. C8 was consistent with first screen results. Adipylcarnitine (C6DC), an organic acid analyte, showed opposite results in the two screens. Several other analytes exhibiting significant associations in the first screen did not in the second. Our results provide evidence that abnormal newborn blood levels of some carnitines may be associated with risk of later ASD, possibly related to their involvement with mitochondrial function in the developing brain.

The association between newborn screening analytes and childhood autism in a Texas Medicaid population, 2010-2012.

Autism (or autism spectrum disorder [ASD]) is an often disabling childhood neurologic condition of mostly unknown cause. It is commonly diagnosed at 3 or 4 years of age. We explored whether there was an association of any analytes measured by newborn screening tests with a later diagnosis of ASD. A database was compiled of 3-5 year-old patients with any ASD diagnosis in the Texas Medicaid system in 2010-2012. Two controls (without any ASD diagnosis) were matched to each case by infant sex and birth year/month. All study subjects were linked to their 2007-2009 birth and newborn screening laboratory records, including values for 36 analytes or analyte ratios. We examined the association of analytes/ratios with a later diagnosis of ASD. Among 3,258 cases and 6,838 controls, seven analytes (e.g., 17-hydroxyprogesterone, acylcarnitines) were associated with a later ASD diagnosis. In this exploratory study, an ASD diagnosis was associated with 7 of 36 newborn screening analytes/ratios. These findings should be replicated in other population-based datasets.

Neonatal nutrition and longitudinal growth in baboons: Adiposity measured by skinfold thickness.

This paper reports the results of a 5 year longitudinal experiment that (1) examined growth in adiposity of a group of 48 clinically normal olive savannah baboons (Papio cynocephalus anubis) who were randomly assigned at birth to one of three diet treatments that differed, during the first 16 weeks, in the amount of nutrients they provided; (2) tested the hypothesis that different amounts of food availability during the neonatal period (birth to 16 weeks) had a significant effect on growth and development of adiposity in the subsequent infant, juvenile, and adolescent periods; and (3) evaluated the extent to which underfed (LC) and overfed (HC) subjects were capable of growth canalization. Each diet contained different caloric densities but the same proportion of fat (34%), carbohydrate (55%), and protein (11%). All animals were fed the same volume of formula; however, HC subject were fed 40% more calories than MC subjects, who were fed 40% more calories than the LC subjects. Growth and development of adiposity were assessed by measuring neck, triceps, subscapular, and suprailiac skinfolds weekly from birth to 16 weeks and at 13 week intervals from 26 to 260 weeks of age. We found that during the first 16 weeks of the experiments, baboon growth was strongly influenced by food shortages but not by excesses; however, when the dietary treatment ceased, growth appeared to be strongly regulated by a genetic component (developmental canalization) and tended to return to a more normal growth pattern within a 26 week time frame. Males and females exhibited differences in adipose development in that males did not exhibit residual treatment effects while females tended to retain the effects of neonatal dietary treatments through early adolescence.

Body composition in baboons: Evaluating a morphometric method.

The objective of this study was to determine whether noninvasive morphometric measurements of olive baboons (Papio cynocephalus anubis) can reliably predict lean body mass and fat mass in this species. Crown-rump length, triceps circumference, and skinfold measures at the neck, subscapular, suprailiac, and triceps sites were obtained prior to necropsy from 21 clinically normal infant baboons at 18 weeks of age and from 22 clinically normal adolescent baboons at 5 years of age. At necropsy, the lean body mass and body fat mass were measured using gravimetric methods. Pearson's correlations and regression analysis were used to test the relationship between direct measures of lean and fat mass obtained at necropsy with calculated estimates based on morphometric measures obtained prior to death. Our null hypothesis was that the morphometric measures (individually or in combination) were not related to direct measures of fat mass or lean mass. Non-linear and multiple regression estimators, by age and gender, were derived and provided increased predictability. Our results indicate that (1) morphometric measures can accurately predict lean body mass in male and female baboons; (2) morphometric measures used to predict lean body mass change with age; (3) morphometric measures are strongly associated with body fat mass at 18 weeks of age but are not as strongly associated with body fat mass in 5-year-old baboons; (4) triceps circumference provides the best single indicator of lean body mass for both genders and age periods; (5) baboons are like humans in that adolescent females tend to accumulate body fat while males of the same age tend to develop lean mass; and (6) combinations of these morphometric measurements explain between 70% and 100% of the variability and can be used to estimate lean and fat mass in baboons.