Cardiorespiratory Monitoring Data to Predict Respiratory Outcomes in Extremely Preterm Infants.

Rationale: Immature control of breathing is associated with apnea, periodic breathing, intermittent hypoxemia, and bradycardia in extremely preterm infants. However, it is not clear if such events independently predict worse respiratory outcome. Objectives: To determine if analysis of cardiorespiratory monitoring data can predict unfavorable respiratory outcomes at 40 weeks postmenstrual age (PMA) and other outcomes, such as bronchopulmonary dysplasia at 36 weeks PMA. Methods: The Prematurity-related Ventilatory Control (Pre-Vent) study was an observational multicenter prospective cohort study including infants born at <29 weeks of gestation with continuous cardiorespiratory monitoring. The primary outcome was either "favorable" (alive and previously discharged or inpatient and off respiratory medications/O2/support at 40 wk PMA) or "unfavorable" (either deceased or inpatient/previously discharged on respiratory medications/O2/support at 40 wk PMA). Measurements and Main Results: A total of 717 infants were evaluated (median birth weight, 850 g; gestation, 26.4 wk), 53.7% of whom had a favorable outcome and 46.3% of whom had an unfavorable outcome. Physiologic data predicted unfavorable outcome, with accuracy improving with advancing age (area under the curve, 0.79 at Day 7, 0.85 at Day 28 and 32 wk PMA). The physiologic variable that contributed most to prediction was intermittent hypoxemia with oxygen saturation as measured by pulse oximetry <90%. Models with clinical data alone or combining physiologic and clinical data also had good accuracy, with areas under the curve of 0.84-0.85 at Days 7 and 14 and 0.86-0.88 at Day 28 and 32 weeks PMA. Intermittent hypoxemia with oxygen saturation as measured by pulse oximetry <80% was the major physiologic predictor of severe bronchopulmonary dysplasia and death or mechanical ventilation at 40 weeks PMA. Conclusions: Physiologic data are independently associated with unfavorable respiratory outcome in extremely preterm infants.

Evaluation of proton-coupled folate transporter (SLC46A1) polymorphisms as risk factors for neural tube defects and oral clefts.

Many folate-related genes have been investigated for possible causal roles in neural tube defects (NTDs) and oral clefts. However, no previous reports have examined the major gene responsible for folate uptake, the proton-coupled folate transporter (SLC46A1). We tested for association between these birth defects and single nucleotide polymorphisms in the SLC46A1 gene. The NTD study population included 549 complete and incomplete case-family triads, and 999 controls from Ireland. The oral clefts study population comprised a sample from Utah (495 complete and incomplete case-family triads and 551 controls) and 221 Filipino multiplex cleft families. There was suggestive evidence of increased NTD case risk with the rs17719944 minor allele (odds ratio (OR): 1.29; 95% confidence intervals (CI): [1.00-1.67]), and decreased maternal risk of an NTD pregnancy with the rs4795436 minor allele (OR: 0.62; [0.39-0.99]). In the Utah sample, the rs739439 minor allele was associated with decreased case risk for cleft lip with cleft palate (genotype relative risk (GRR): 0.56 [0.32-0.98]). Additionally, the rs2239907 minor allele was associated with decreased case risk for cleft lip with cleft palate in several models, and with cleft palate only in a recessive model (OR: 0.41; [0.20-0.85]). These associations did not remain statistically significant after correcting for multiple hypothesis testing. Nominal associations between SLC46A1 polymorphisms and both Irish NTDs and oral clefts in the Utah population suggest some role in the etiology of these birth defects, but further investigation in other populations is needed.

Replication and exploratory analysis of 24 candidate risk polymorphisms for neural tube defects.

BACKGROUND: Neural tube defects (NTDs), which are among the most common congenital malformations, are influenced by environmental and genetic factors. Low maternal folate is the strongest known contributing factor, making variants in genes in the folate metabolic pathway attractive candidates for NTD risk. Multiple studies have identified nominally significant allelic associations with NTDs. We tested whether associations detected in a large Irish cohort could be replicated in an independent population. METHODS: Replication tests of 24 nominally significant NTD associations were performed in racially/ethnically matched populations. Family-based tests of fifteen nominally significant single nucleotide polymorphisms (SNPs) were repeated in a cohort of NTD trios (530 cases and their parents) from the United Kingdom, and case-control tests of nine nominally significant SNPs were repeated in a cohort (190 cases, 941 controls) from New York State (NYS). Secondary hypotheses involved evaluating the latter set of nine SNPs for NTD association using alternate case-control models and NTD groupings in white, African American and Hispanic cohorts from NYS. RESULTS: Of the 24 SNPs tested for replication, ADA rs452159 and MTR rs10925260 were significantly associated with isolated NTDs. Of the secondary tests performed, ARID1A rs11247593 was associated with NTDs in whites, and ALDH1A2 rs7169289 was associated with isolated NTDs in African Americans. CONCLUSIONS: We report a number of associations between SNP genotypes and neural tube defects. These associations were nominally significant before correction for multiple hypothesis testing. These corrections are highly conservative for association studies of untested hypotheses, and may be too conservative for replication studies. We therefore believe the true effect of these four nominally significant SNPs on NTD risk will be more definitively determined by further study in other populations, and eventual meta-analysis.

Bone mineral density in young women with primary ovarian insufficiency: results of a three-year randomized controlled trial of physiological transdermal estradiol and testosterone replacement.

CONTEXT: Women with primary ovarian insufficiency have significantly lower serum estradiol and T levels compared with regularly menstruating women. They also have significantly reduced bone mineral density (BMD). OBJECTIVE: The objective of the study was to evaluate the efficacy of hormone replacement in maintaining BMD in these young women. DESIGN AND SETTING: This was a randomized, double-blind, single-center, placebo-controlled clinical trial at the National Institutes of Health clinical center (Bethesda, Maryland). PARTICIPANTS: Young women with primary ovarian insufficiency participated in the study. INTERVENTIONS: We compared the effect of estradiol and progestin replacement (n = 72) vs estradiol, progestin, and T replacement (n = 73) on BMD. We also compared findings with a contemporaneous control group of normal women (n = 70). All patients received transdermal estradiol (100 µg/d) plus oral medroxyprogesterone acetate 10 mg/d (12 d/mo) for a 3-month run-in period before being randomized in a double-blinded fashion to the addition of transdermal T (150 µg/d) or placebo. MAIN OUTCOME MEASURE: Change in BMD at the femoral neck was measured by dual-energy x-ray absorptiometry. RESULTS: At screening, patients had significantly lower femoral neck BMD compared with control women (0.77 vs 0.81 g/cm(2), P = .001) and did not differ in body mass index, age at menarche, or education level. Normal control women lost femoral neck BMD over the study period, whereas patients on estradiol and progestin therapy gained BMD; and at the end of the study period, femoral neck BMD of patients on estradiol and progestin therapy did not differ from that of control women (0.80 g/cm(2) in both groups, P = .9). The addition of T showed no further benefit (percentage change in BMD 3.9 vs 2.4, respectively, P = .9). Nonetheless, using a repeated-measures model, the T group achieved a mean BMD in the femoral neck 0.015 g/cm(2) higher than the placebo group at 3 years (95% confidence interval -0.005 to 0.034, P = .13). Similar findings were observed in the lumbar spine BMD as well. CONCLUSION: Long-term physiological transdermal estradiol replacement in combination with oral medroxyprogesterone acetate restores mean femoral neck BMD to normal in young women with spontaneous 46,XX primary ovarian insufficiency. However, the addition of physiological transdermal T replacement did not provide additional benefit.

Evaluation of common genetic variants in 82 candidate genes as risk factors for neural tube defects.

BACKGROUND: Neural tube defects (NTDs) are common birth defects (~1 in 1000 pregnancies in the US and Europe) that have complex origins, including environmental and genetic factors. A low level of maternal folate is one well-established risk factor, with maternal periconceptional folic acid supplementation reducing the occurrence of NTD pregnancies by 50-70%. Gene variants in the folate metabolic pathway (e.g., MTHFR rs1801133 (677 C > T) and MTHFD1 rs2236225 (R653Q)) have been found to increase NTD risk. We hypothesized that variants in additional folate/B12 pathway genes contribute to NTD risk. METHODS: A tagSNP approach was used to screen common variation in 82 candidate genes selected from the folate/B12 pathway and NTD mouse models. We initially genotyped polymorphisms in 320 Irish triads (NTD cases and their parents), including 301 cases and 341 Irish controls to perform case-control and family based association tests. Significantly associated polymorphisms were genotyped in a secondary set of 250 families that included 229 cases and 658 controls. The combined results for 1441 SNPs were used in a joint analysis to test for case and maternal effects. RESULTS: Nearly 70 SNPs in 30 genes were found to be associated with NTDs at the p < 0.01 level. The ten strongest association signals (p-value range: 0.0003-0.0023) were found in nine genes (MFTC, CDKN2A, ADA, PEMT, CUBN, GART, DNMT3A, MTHFD1 and T (Brachyury)) and included the known NTD risk factor MTHFD1 R653Q (rs2236225). The single strongest signal was observed in a new candidate, MFTC rs17803441 (OR = 1.61 [1.23-2.08], p = 0.0003 for the minor allele). Though nominally significant, these associations did not remain significant after correction for multiple hypothesis testing. CONCLUSIONS: To our knowledge, with respect to sample size and scope of evaluation of candidate polymorphisms, this is the largest NTD genetic association study reported to date. The scale of the study and the stringency of correction are likely to have contributed to real associations failing to survive correction. We have produced a ranked list of variants with the strongest association signals. Variants in the highest rank of associations are likely to include true associations and should be high priority candidates for further study of NTD risk.

A prospective evaluation of antral follicle function in women with 46,XX spontaneous primary ovarian insufficiency.

OBJECTIVE: To assess ovarian follicle function in women with 46,XX spontaneous primary ovarian insufficiency. DESIGN: Case-control with nested prospective cohort. SETTING: Clinical Research Center, National Institutes of Health. PATIENT(S): Women with primary ovarian insufficiency without estrogen replacement for 2 weeks (N = 97) and regularly menstruating control women (N = 42). INTERVENTION(S): Single injection of 300 IU hrFSH. MAIN OUTCOME MEASURE(S): Change in serum estradiol at 24 hours. RESULT(S): Antral follicles ≥3 mm were detected in 73% (69/95) of patients; both serum estradiol and progesterone levels correlated significantly with maximum follicle diameter in these women. Patients with a maximum follicle diameter ≥8 mm had significantly higher serum estradiol and progesterone levels and significantly lower FSH and LH levels compared with patients without such follicles. In controls estradiol levels increased significantly after FSH administration, but in patients this was not the case despite the presence of an antral follicle ≥8 mm. CONCLUSION(S): Most women with 46,XX spontaneous primary ovarian insufficiency have antral follicles detectable by ultrasound, suggesting that down-regulation of FSH receptors is not the predominant mechanism of follicle dysfunction. Evidence of progesterone secretion by antral follicles ≥8 mm in these patients is consistent with prior histologic evidence that follicle luteinization is the predominant mechanism of follicle dysfunction in this condition. Prospective controlled investigation designed to improve ovulatory function and fertility in these women is indicated.

Lack of association between folate-receptor autoantibodies and neural-tube defects.

BACKGROUND: A previous report described the presence of autoantibodies against folate receptors in 75% of serum samples from women with a history of pregnancy complicated by a neural-tube defect, as compared with 10% of controls. We sought to confirm this finding in an Irish population, which traditionally has had a high prevalence of neural-tube defects. METHODS: We performed two studies. Study 1 consisted of analysis of stored frozen blood samples collected from 1993 through 1994 from 103 mothers with a history of pregnancy complicated by a neural-tube defect (case mothers), 103 mothers with a history of pregnancy but no complication by a neural-tube defect (matched with regard to number of pregnancies and sampling dates), 58 women who had never been pregnant, and 36 men. Study 2, conducted to confirm that the storage of samples did not influence the folate-receptor autoantibodies, included fresh samples from 37 case mothers, 22 control mothers, 10 women who had never been pregnant, and 9 men. All samples were assayed for blocking and binding autoantibodies against folate receptors. RESULTS: In Study 1, blocking autoantibodies were found in 17% of case mothers, as compared with 13% of control mothers (odds ratio, 1.54; 95% confidence interval [CI], 0.70 to 3.39), and binding autoantibodies in 29%, as compared with 32%, respectively (odds ratio, 0.82; 95% CI, 0.44 to 1.50). Study 2 showed similar results, indicating that sample degradation was unlikely. CONCLUSIONS: The presence and titer of maternal folate-receptor autoantibodies were not significantly associated with a neural-tube defect-affected pregnancy in this Irish population.

Bone mineral density in estrogen-deficient young women.

CONTEXT: Osteoporosis primarily affects postmenopausal women. However, young women with estrogen deficiency also are at increased risk for low bone density. OBJECTIVE: The aim of the study was to assess bone density and associated risk factors for reduced bone density in young, estrogen-deficient women using primary ovarian insufficiency (POI) as the disease model. DESIGN AND SETTING: We conducted a cross-sectional study at a tertiary care research center. PARTICIPANTS: We studied women with POI (n = 442), concurrent controls (n = 70), and matched controls from NHANES III (n = 353). PRIMARY OUTCOME MEASURE: We measured bone mineral density (BMD) using dual-energy x-ray absorptiometry. RESULTS: Patients on average had 2-3% lower BMD at L1-L4, femoral neck, and total hip (P < 0.01 at all sites). The modifiable risk factors for BMD below the expected range for age (Z-score <-2) were: more than 1-yr delay in diagnosis of estrogen deficiency (P = 0.018), low (<32 ng/ml) vitamin D levels (P = 0.002), estrogen replacement nonadherence (P = 0.002), low calcium intake (P = 0.005), and lack of exercise (P = 0.005). As compared to Caucasians, African-American and Asian women with POI were 3.18 and 4.34 times more likely, respectively, to have Z-scores below -2 (P = < 0.0001 for both). Race was an overall risk factor, but on regression modeling, not an independent predictor of low bone density. CONCLUSIONS: Women with POI have lower bone density compared to regularly menstruating women. Compared to Caucasians, minority women with estrogen deficiency are more likely to have BMD below the expected range for age. This racial disparity appears to be related to a combined effect of several modifiable risk factors. Delay in diagnosis of POI also contributes to reduced bone density by delaying proper therapy.

Maternal vitamin B12 status and risk of neural tube defects in a population with high neural tube defect prevalence and no folic Acid fortification.

OBJECTIVE: Folic acid fortification has reduced neural tube defect prevalence by 50% to 70%. It is unlikely that fortification levels will be increased to reduce neural tube defect prevalence further. Therefore, it is important to identify other modifiable risk factors. Vitamin B(12) is metabolically related to folate; moreover, previous studies have found low B(12) status in mothers of children affected by neural tube defect. Our objective was to quantify the effect of low B(12) status on neural tube defect risk in a high-prevalence, unfortified population. METHODS: We assessed pregnancy vitamin B(12) status concentrations in blood samples taken at an average of 15 weeks' gestation from 3 independent nested case-control groups of Irish women within population-based cohorts, at a time when vitamin supplementation or food fortification was rare. Group 1 blood samples were from 95 women during a neural tube defect-affected pregnancy and 265 control subjects. Group 2 included blood samples from 107 women who had a previous neural tube defect birth but whose current pregnancy was not affected and 414 control subjects. Group 3 samples were from 76 women during an affected pregnancy and 222 control subjects. RESULTS: Mothers of children affected by neural tube defect had significantly lower B(12) status. In all 3 groups those in the lowest B(12) quartiles, compared with the highest, had between two and threefold higher adjusted odds ratios for being the mother of a child affected by neural tube defect. Pregnancy blood B(12) concentrations of <250 ng/L were associated with the highest risks. CONCLUSIONS: Deficient or inadequate maternal vitamin B(12) status is associated with a significantly increased risk for neural tube defects. We suggest that women have vitamin B(12) levels of >300 ng/L (221 pmol/L) before becoming pregnant. Improving B(12) status beyond this level may afford a further reduction in risk, but this is uncertain.

Normalization of serum luteinizing hormone levels in women with 46,XX spontaneous primary ovarian insufficiency.

OBJECTIVE: To determine the proportion of women with primary ovarian insufficiency who achieve normal serum LH levels on transdermal E(2) therapy. DESIGN: Prospective. SETTING: Clinical research center at a national US health research facility. PATIENT(S): Women with spontaneous primary ovarian insufficiency (n = 137) and 70 regularly menstruating control women (n = 70). INTERVENTION(S): Blood sampled from controls in the midfollicular phase and from patients while they were off E(2) for 2 weeks, then again 3 months later during the E(2)-only phase of hormone therapy (E(2) patch [100 microg/d] and oral medroxyprogesterone acetate [10 mg for 12 d/mo]). MAIN OUTCOME MEASURE(S): Serum LH. RESULT(S): While on transdermal E(2) therapy, significantly more women (51.1%, 70/137; 95% confidence interval, 42%, 60%) had serum LH levels in the normal range (5/137, 3.9% at baseline). Mean (SD) serum E(2) level significantly increased on therapy to 95.4 (84.9) pg/mL. CONCLUSION(S): A regimen of 100 microg/d of transdermal E(2) therapy achieves normal serum LH levels in approximately one half of women with spontaneous primary ovarian insufficiency. Theoretically, by avoiding inappropriate luteinization, physiologic E(2) therapy may improve follicle function in these women. Controlled studies to assess the effect of transdermal E(2) therapy on follicle function in these women are warranted.

Sexual function in young women with spontaneous 46,XX primary ovarian insufficiency.

OBJECTIVE: To assess sexual function in women with spontaneous 46,XX primary ovarian insufficiency after at least 3 months of a standardized hormone replacement regimen. DESIGN: Cross-sectional cohort, controlled. SETTING: National Institutes of Health Clinical Research Center. PATIENT(S): Women with primary ovarian insufficiency (n = 143) and regularly menstruating controls (n = 70). INTERVENTION(S): Self-administered questionnaires, 100 microg/day E(2) patch, oral medroxyprogesterone acetate 10 mg for 12 days each month for patients. MAIN OUTCOME MEASURE(S): Derogatis Interview for Sexual Function Self-Report (DISF-SR). RESULT(S): Women with primary ovarian insufficiency had significantly lower DISF-SR composite scores compared with control women. Their serum total testosterone levels were significantly correlated with DISF-SR composite score, although this accounted for only 4% of the variance in this measure. Patients with testosterone levels below normal tended to have lower DISF-SR composite scores. Of patients with primary ovarian insufficiency, 9 of 127 (7%) scored below the second percentile on the composite sexual function score, compared with 1 of 49 control women (2%). CONCLUSION(S): As assessed by the DISF-SR, sexual function is in the normal range for most young women with 46,XX spontaneous primary ovarian insufficiency who are receiving physiologic E(2) replacement. However, as a group, these young women score significantly lower on this sexual function scale than control women.