Mary L. Hediger

Prenatal DDT Exposure in Relation to Anthropometric and Pubertal Measures in Adolescent Males

DDT (dichlorodiphenyltrichloroethane), a pesticide once used widely in agriculture and now limited to public health use, remains a controversial chemical because of a combination of benefits and risks. DDT or its breakdown products are ubiquitous in the environment and in humans. Compounds in the DDT family have endocrine actions and have been associated with reproductive toxicity. A previous study reported associations between prenatal exposure to p,p′-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene] and increased height and weight in adolescent boys. We examined a group with higher exposures to see whether similar associations would occur. Our study group was 304 males born in Philadelphia in the early 1960s who had participated in a previous study. Anthropometric and pubertal measures from one to six visits during their adolescent years were available, as were stored maternal serum samples from pregnancy. We measured p,p′-DDE, p,p′-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)-ethane], and o,p′-DDT [1,1,1-trichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)-ethane] in the maternal serum. Outcomes examined in the boys were height, ratio of sitting height to height, body mass index, triceps skinfold thickness, ratio of subscapular to the sum of triceps and subscapular skinfold thicknesses, skeletal age, serum testosterone, and serum dehydroepiandrosterone sulfate. No associations between prenatal exposure to any of the DDT compounds and any outcome measure were seen.

Age at menarche based on recall information

Censored likelihood methods which use recalled dates yield accurate estimates of the age at menarche in an urban population of black adolescent girls. The mean age at menarche is 12.44 (SE 0.08) years for a sample of 272 black adolescents in Philadelphia, PA. The methodology we describe is more efficient than logit or probit methods, which are not designed to utilize recall information. Alternative methods which use recall are biased if subject memory is influenced by length of time since menarche. Our methods also provide information on the nature of subject recall that may be useful in further analysis.

Blood pressure, body fat, and dehydroepiandrosterone sulfate variation in adolescence.

Several significant interrelations among variation in blood pressure, body fat, and adrenal androgen levels, as assessed by serum dehydroepiandrosterone sulfate concentrations, were found in black male and female adolescents, aged 12 to 16 years. In girls, high levels of dehydroepiandrosterone sulfate were associated with significantly higher levels of blood pressure (alpha = 0.05), even after adjusting for the significant association between increased levels of dehydroepiandrosterone sulfate and body fat. The increased body fat (i.e., body mass index) found with higher levels of dehydroepiandrosterone sulfate in girls was related to significantly greater (alpha = 0.05) accumulations of fat in the upper trunk, as opposed to the limb. In boys, high levels of serum dehydroepiandrosterone sulfate, low body mass index, and significantly higher blood pressure were interrelated (alpha = 0.05). In addition to the interaction of increased body mass index or body fat and increased levels of dehydroepiandrosterone sulfate in association with higher blood pressure, high levels of the adrenal androgen, even in boys with low body mass index, were associated independently with relatively higher blood pressure. Body proportion analyses for these boys indicated that they were tall and thin, in contrast to the other boys with low body mass index, who were generally short and thin.

Low-Level Lead Exposure in Childhood Influences Neuropsychological Performance

Cumulative lead exposure in 193 inner-city black children was assessed by measuring lead concentrations in the primary and circumpulpal dentine of their deciduous teeth. Lead concentrations for these children were comparable to the concentrations reported in population studies of low-income children living in inner-city areas. Analysis of the childrens neuropsychological test performance showed that elevated lead levels were associated with deficits in visual-motor functioning and perceptual integration, right-left orientation, and verbal abstraction; other verbal abilities and motor functioning were not affected. Possible alternative explanations for these findings were evaluated by examining the relationships between lead and maternal intelligence, family socioeconomic status, and perinatal indicators of neurological impairment. None of these relationships was significant. It was concluded that, even at levels usually regarded as asymptomatic, lead in the environment represents a hazard to inner-city children.

Concurrent validity studies of blood pressure instrumentation. The Philadelphia Blood Pressure Project.

There is increasing evidence that blood pressure (BP) screening during adolescence may detect early evidence of hypertensive disease. Choice of instrumentation becomes important to maximize the accuracy and interpretive value of several serial readings. We therefore conducted two studies of adolescents, comparing auscultatory (Baumanometer and Random-zero), ultrasonic (Arteriosonde 1216), and infrasonic (Physiometrics SR-2) devices. These instruments were compared serially (Study 1) for older adolescents (n = 48). The Baumanometer, Arteriosonde 1216, and Physiometrics SR-2 were compared both serially and simultaneously (Study 2) for younger and older adolescents (n = 24). In both studies, the order of device presentation was completely counterbalanced. In Study 1, reliability estimates were high (r greater than 0.65), with the exception of the Arteriosonde 1216 diastolic readings, and the Physiometrics SR-2 yielded significantly lower mean diastolic BP readings than the other devices. Diastolic Phase V readings taken with the Random-zero were significantly higher when the Random-zero was presented at the end of the sequence of instrument presentation. This order of presentation effect is probably attributable to the need for overinflation when using the Random-zero device and may cause an overestimation of diastolic BP in the young. In Study 2, again the Arteriosonde 1216 did not perform reliably in recording diastolic BP. Further, the Physiometrics SR-2 device, although reliable, yielded diastolic readings significantly lower (p less than 0.001) than diastolic Phase IV readings taken both serially and simultaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

High-dose vitamin D3 supplementation in children and young adults with HIV: a randomized, placebo-controlled trial.

Background: Suboptimal vitamin D status is prevalent in HIV-infected patients and associated with increased risk of disease severity and morbidity. We aimed to determine 12-month safety and efficacy of daily 7000 IU vitamin D3 (vitD3) versus placebo to sustain increased serum 25-hydroxyvitamin D (25(OH)D) and improve immune status in HIV-infected subjects. Methods: This was a double-blind trial of perinatally acquired HIV (PHIV)-infected subjects or behaviorally acquired HIV (BHIV)-infected subjects (5.0-24.9 years). Safety, 25(OH)D-related parameters and immune status were assessed at baseline, 3, 6 and 12 months. Results: Fifty-eight subjects enrolled (67% male, 85% African American and 64% BHIV) and 50 completed with no safety concerns. In unadjusted analyses, there were no differences between randomization groups at baseline; at 3, 6 and 12 months, 25(OH)D was higher with supplementation than baseline and higher than with placebo (P < 0.05). In adjusted mixed models, in the supplementation group, the fixed effect of 25(OH)D was higher (P < 0.001). Percentage of naive T-helper cells (Th naive%) were significantly (P < 0.01) and T-helper cells (CD4%) marginally (P < 0.10) increased with supplementation in those taking highly active antiretroviral therapy (HAART), and RNA viral load was reduced (P ⩽ 0.05). In exploratory linear models, change in 25(OH)D predicted RNA viral load at 3 and 12 months and CD4% at 3 months (P < 0.05). Conclusions: Daily 7000 IU vitD3 for 12 months was safe in HIV-infected subjects and effective in increasing 25(OH)D. Supplementation improved some clinically important HIV immune markers in subjects on HAART. Adjunct therapy with high-dose, daily vitD3 for HIV-infected subjects and for those on/off HAART requires further investigation.

Age at hormonal onset of puberty based on luteinizing hormone, inhibin B, and body composition in preadolescent US girls

Background:Hormonal indicators could be useful for detecting early pubertal onset, but there is little research on how they are related to puberty in US girls. We determined median age at hormonal onset of puberty based on luteinizing hormone (LH) and inhibin B (InB) and explored the extent to which body composition moderates this timing process.Methods:We analyzed anthropometric and hormone data of 698 US peri-pubertal girls ages 6–11.99 y who had participated in the Third National Health and Nutrition Examination Survey (NHANES III), 1988–1994.Results:Median age of hormonal onset of puberty was 10.43 y by LH and 10.08 y by InB cut-offs (1.04 mIU/ml for LH and 17.89 pg/ml for InB). Postnatal weight gain modulated onset, making it earlier by 10–11 mo among the highest (greater than +1 SD) relative to normal weight gainers. Onset occurred first in non-Hispanic black (NHB) girls, 10.08 y (95% confidence interval (CI): 10.07–10.09), followed by Mexican-American (MXAM) at 10.64 y (95% CI: 10.63–10.65), and at 10.66 y (95% CI: 10.66–10.67) for non-Hispanic white (NHW) girls using LH. With InB, onset occurred first in MXAM girls at 9.9 y, and at 10.3 y and 10.4 y for their NHB and NHW peers, respectively.Conclusion:Preadolescent weight gain lowers the age at hormonal onset as defined by LH concentrations. Preventing obesity in childhood may also avert the earlier initiation of the maturation process even at the hormonal level.

Nausea and vomiting during teenage pregnancy: Effects on birth weight☆

Early pregnancy nausea and vomiting (NVP) has been reported to be a favorable risk factor for pregnancy outcome. We studied nausea and vomiting in 239 randomly selected teens from a geographic-based cohort of nearly 2800 pregnant adolescents from Camden County, New Jersey. Early (first trimester) NVP was reported by 20.9%, and an additional 17.6% reported that their NVP persisted into the second or third trimester (late NVP). After adjusting for confounding factors (length of gestation, maternal age, ethnicity, prepregnant body mass index, weight gain, and smoking), we found that early NVP alone did not significantly affect birth weight. Late NVP, however, was associated with a significant decrement in birth weight (-256.5 +/- 108.0 g, p less than 0.05). Further, the effect of late NVP was greater when maternal weight gain was inadequate. Teenagers with continued NVP are more likely to be nutritionally stressed during the course of their pregnancy.

Are Maternal and Sonographic Factors Associated With the Detection of a Fetal Echogenic Cardiac Focus

To evaluate the influence of maternal weight and the orientation of the fetal 4‐chamber heart view on the detection of a fetal echogenic cardiac focus.

Variability and reliability of diastolic blood pressure during adolescence: The Philadelphia blood pressure project

This paper reports results of diastolic blood pressure studies done as part of the Philadelphia Blood Pressure Project (PBPP), a 3-year longitudinal study of black adolescents, initially ages 11–15, who were enrolled originally in the Philadelphia Collaborative Perinatal Project (CPP). Three samples were studied by the PBPP: a representative sample of over 500 black adolescents stratified by age and sex, a smaller sample of adolescents who had blood pressures elevated beyond one standard deviation of the CPP population mean at age 7, and a sample of adolescents born of toxemic pregnancies. We found, for the representative sample, consistent differences in the means of diastolic blood pressure phases IV and V and between diastolic blood pressures taken in supine and seated positions. Supine diastolic blood pressures were more variable at every age and were lower than the comparable seated diastolic blood pressures. In addition, we estimated on a random subsample from all three samples diastolic blood pressure reliability for supine readings taken sequentially by the same (N = 96) and different (N = 55) examiners. We also estimated measurement reliability simultaneously (N = 91 supine, N = 96 seated) using a double-listening stethoscope. We found that although diastolic phase IV blood pressure was more reproducible or less variable over short periods of time (5–15 min) when reliability measures were taken sequentially, two examiners simultaneously could not measure phase IV with significantly greater accuracy than phase V. We concluded that the fourth and fifth Korotkoff sounds should not be used interchangeably during adolescence and that postural position is an important contributor to diastolic blood pressure variance during adolescence. Also, since it has not yet been established which is more statistically predictive of adult blood pressure levels, whenever possible, both phase IV and V should be recorded for adolescents.