Biomedical subjects

S L Carmichael

Publications and source records attributed to S L Carmichael.

15 recordsLinked to original sources

PubMed2006

Correlates of intake of folic acid-containing supplements among pregnant women.

OBJECTIVE: This study describes the timing and correlates of folic acid supplement intake among pregnant women. STUDY DESIGN: Data from 2518 women with estimated delivery dates from 1997 to 2000, collected for the National Birth Defects Prevention Study, a population-based case-control study, were analyzed. Multinomial logistic regression was used to identify correlates of supplement intake. RESULTS: Fifty-three percent of women began taking folic acid supplement during the periconceptional period, 35% during early pregnancy, and 8% during late pregnancy (ie, 3 months before through 1 month after conception, 2-3 months after conception, or more than 3 months after conception, respectively). Women who did not take folic acid supplement periconceptionally tended to be nonwhite, speak Spanish, have low education, be younger than 25 years old, be nulliparous, smoke, have no previous miscarriage and no fertility treatments, begin prenatal care and become aware of their pregnancy after the first trimester, have nonplanned pregnancies, and eat less breakfast cereal. CONCLUSION: This study identifies correlates of folic acid supplement intake, which may contribute to the design of interventions to improve intake during early pregnancy.

Adolescent↗

PubMed2001

Breast-feeding practices among WIC participants in Hawaii.

OBJECTIVE: To describe breast-feeding practices and identify correlates of breast-feeding among participants in the Hawaii Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) program. DESIGN: A cross-sectional survey. SUBJECTS/SETTING: We conducted structured, in-person interviews with 535 women at WIC clinics throughout Hawaii (95% response rate). The interview collected information on maternal characteristics and infant-feeding practices. STATISTICAL ANALYSES: Breast-feeding prevalence was examined by infant age and predictors of infant-feeding method were examined via bivariate tests and multivariable logistic regression analysis. Reported breast-feeding promotion efforts in health care settings outside of WIC were also examined. RESULTS: Most women (82%) attempted to breast-feed, albeit for short durations for many women; of the women who breast-fed in combination with formula feeding, 46% introduced formula within the first week after delivery. Significant predictors of breast-feeding initiation included previous breast-feeding experience, having a close relative or friend who breast-fed, multiparity, Asian/Pacific Island ethnicity (other than Filipino), and being foreign-born. Significant predictors of mixed feeding (vs exclusive breast-feeding) included working or attending school, age less than 20 years, Hawaiian/part Hawaiian or Filipino ethnicity, being Hawaiian-born, and residing in Oahu county. CONCLUSIONS: Although most women in this population initiated breast-feeding, formula was usually introduced at an early age. This study identified several factors associated with breast-feeding initiation and exclusive breast-feeding, factors that may prove useful for the development of appropriate interventions to promote these behaviors.

Adult↗

PubMed2001

Lowered weight gain during pregnancy and risk of neural tube defects among offspring.

BACKGROUND: Maternal nutritional factors have been implicated in the complex aetiology of neural tube defects (NTD). We investigated whether the amount of weight a woman gained during pregnancy was associated with her risk of delivering an infant with an NTD. METHODS: We conducted a population-based case-control study within the cohort of 708 129 live births and fetal deaths occurring in selected California counties in 1989-1991. Face-to-face interviews were conducted with mothers of 538 (88% of eligible) NTD cases (including those electively terminated, stillborn, or liveborn) and with mothers of 539 (88%) non-malformed liveborn controls within an average of 5 months from the term delivery date. Respondent-reported weight gain during pregnancy (kg) was analysed. Risks of infants having NTD were estimated among women who gained <10 kg compared to those who gained > or =10 kg during > or =38 week gestations. RESULTS: Compared to women who gained > or =10 kg, an increased risk for NTD offspring was observed among women who gained <10 kg (odds ratio [OR] = 3.2, 95% CI : 2.3-4.6). The OR was 5.0 (95% CI : 2.6-9.7) among those women who gained <5 kg during pregnancy. The increased risk was not attributable to maternal non-use of a multivitamin containing folic acid, diabetes, NTD-pregnancy history, age, race/ethnicity, education, gravidity, alcohol use, cigarette use, prepregnant obesity, low socioeconomic status, dieting, nausea, nor to lower dietary intakes of folate, zinc, energy, protein, fat, carbohydrates, and methionine. An increased risk was observed even after simultaneous adjustment for most of these factors (OR = 2.2, 95% CI : 1.2-3.8). The risk associated with gaining <10 kg was greater for anencephaly, but still elevated for spina bifida. CONCLUSIONS: We did not have information on weight gain during early pregnancy. Because weight gain during the relevant embryological period for NTD (first month post-conception) is relatively small and often variable, it seems less likely that elevated NTD risks indicate a causal association between lowered weight gain throughout pregnancy and abnormal development of the neural tube. It seems more likely that lowered weight gain is a consequence of carrying an NTD-affected fetus. However, what this consequence is and why risk was substantially larger for anencephaly is unknown.

Adult↗

PubMed2001

The National Birth Defects Prevention Study.

The National Birth Defects Prevention Study was designed to identify infants with major birth defects and evaluate genetic and environmental factors associated with the occurrence of birth defects. The ongoing case-control study covers an annual birth population of 482,000 and includes cases identified from birth defect surveillance registries in eight states. Infants used as controls are randomly selected from birth certificates or birth hospital records. Mothers of case and control infants are interviewed and parents are asked to collect buccal cells from themselves and their infants for DNA testing. Information gathered from the interviews and the DNA specimens will be used to study independent genetic and environmental factors and gene-environment interactions for a broad range of birth defects. As of December 2000, 7,470 cases and 3,821 controls had been ascertained in the eight states. Interviews had been completed with 70% of the eligible case and control mothers, buccal cell collection had begun in all of the study sites, and researchers were developing analysis plans for the compiled data. This study is the largest and broadest collaborative effort ever conducted among the nation's leading birth defect researchers. The unprecedented statistical power that will result from this study will enable scientists to study the epidemiology of some rare birth defects for the first time. The compiled interview data and banked DNA of approximately 35 categories of birth defects will facilitate future research as new hypotheses and improved technologies emerge.

Case-Control Studies↗

PubMed2000

Correlates of postpartum smoking relapse. Results from the Pregnancy Risk Assessment Monitoring System (PRAMS).

BACKGROUND: Using population-based data from the Pregnancy Risk Assessment Monitoring System (PRAMS), this study examines the prevalence and intensity of smoking before, during, and after pregnancy, and identifies correlates of postpartum smoking relapse. METHODS: Women who delivered live births in 1996 responded to a mailed questionnaire approximately 2 to 6 months after delivery (N =17,378). Data from 10 states participating in PRAMS were included in the study, and the overall participation rate was 75%. Analyses were adjusted for survey design and sampling strategy. Logistic regression analysis identified independent correlates of smoking relapse. RESULTS: Overall, 25.6% of women reported cigarette smoking before pregnancy. Among women who smoked before pregnancy, 44.5% quit during pregnancy. Among women who quit during pregnancy, half relapsed by the time of the survey. Independent correlates associated with increased risk of postpartum relapse included African American race/ethnicity, multiparity, high maternal weight gain, late or no prenatal care, and stressful life events. CONCLUSIONS: Correlates of postpartum smoking relapse identified by this study may contribute to the development of effective and targeted interventions to maintain long-term smoking cessation.

Adult↗

PubMed2000

Maternal life event stress and congenital anomalies.

We used data from a population-based case-control study to explore the relation between certain life events during the periconceptional period and several types of congenital anomalies. We ascertained cases from pregnancies ending in 1987-1989 and randomly selected controls from eligible liveborn infants. In telephone interviews, women reported deaths of anyone close to them. They also reported job losses or separations/divorces, for themselves or anyone close to them. Experiencing at least one stressful event during the periconceptional period was associated with a prevalence odds ratio of 1.4-1.5 for the delivery of infants with conotruncal heart defects, neural tube defects, and isolated cleft lip with or without palate. These associations tended to be restricted to women who were not obese and women with less than or equal to a high school education. This study suggests that women who experience stressful life events around the time of conception or early gestation may be at increased risk of delivering infants with certain congenital anomalies.

Congenital Abnormalities↗

PubMed1999

Maternal corticosteroid use and risk of selected congenital anomalies.

Evidence for the teratogenicity of corticosteroids in humans is limited and has resulted in inconsistent recommendations regarding their use during early pregnancy. We examined the association between women's corticosteroid use during the periconceptional period (1 month before to 3 months after conception) and delivering infants with selected congenital anomalies. Data were derived from a population-based case-control study that included cases of orafacial clefts (n = 662), conotruncal heart defects (n = 207), neural tube defects (n = 265), and limb reduction defects (n = 165). Information on medication use was collected via maternal telephone interviews. Corticosteroid use was associated with an increased risk for isolated cleft lip with or without cleft palate (odds ratio 4.3, 95% confidence interval 1.1-17.2) and isolated cleft palate (odds ratio 5.3, 95% confidence interval 1.1-26.5). Increased risks were not observed for the other anomaly groups studied. These data in conjunction with other epidemiologic data suggest a possible causal association between cleft lip and palate and corticosteroid use.

Abnormalities, Drug-Induced↗

PubMed1999

Validity and reproducibility of a food frequency interview in a Multi-Cultural Epidemiology Study.

PURPOSE: There is limited support for the validity and reproducibility of dietary assessment in culturally diverse populations. The goal of this study was to evaluate the comparative validity and reproducibility of a Food Frequency Questionnaire (FFQ) used in the observational, multi-cultural Insulin Resistance Atherosclerosis Study (IRAS). METHODS: Women (n = 186) were approximately equally distributed by ethnicity from one urban center (African Americans and non-Hispanic whites) and one rural center (Hispanics and non-Hispanic whites). The IRAS FFQ was modified from the National Cancer Institute Health Habits and History Questionnaire to include ethnic and regional foods. Validity was assessed by comparing dietary values, including supplements, obtained from the FFQ to the average intake estimated from a series of 8 24-hour dietary recalls collected by telephone over the same 1-year period. Reproducibility was assessed among women who reported no change in their usual diet (n = 133) by comparing data from the original IRAS FFQ (in-person) with the FFQ administered for the validity study (two to four years later, by telephone). RESULTS: Correlation coefficients for validity were statistically significant for most nutrients (mean r = 0.62 urban non-Hispanic white, 0.61 rural non-Hispanic whites, 0.50 African American, 0.41 Hispanic) and did not differ among subgroups of obesity or diabetes status. The median correlation coefficient for the total sample was 0.49. Correlations were lower for women with less than 12 years of education (mean r = 0.30; median r = 0.25). The lower correlations among Hispanics was largely explained by the lower educational attainment in that sample. For reproducibility, the mean correlation for nutrients evaluated was r = 0.62 (median r = 0.63) and did not differ for subgroups. CONCLUSIONS: Although educational attainment must be considered, the IRAS FFQ appears to be reasonably valid and reliable in a diverse cohort.

Adult↗

PubMed1998

Psychiatric morbidity in endocrine disorders.

Psychiatric disturbances are frequently observed during the course of endocrine disorders. This article discusses the history, current knowledge, assessment, and treatment of psychiatric morbidity in endocrine disorders. The primary focus is on biologic links between psychiatric symptoms and endocrine dysfunction. Psychiatric disorders associated with abnormalities of the pituitary, thyroid, parathyroids, adrenals, and gonads are discussed as well as the chronic illness of diabetes mellitus.

Endocrine System Diseases↗

PubMed1998

Changes in the black-white infant mortality gap from 1983 to 1991 in the United States.

BACKGROUND: The long-standing difference in infant mortality in the United States between black and white infants has increased in recent years. To help identify the cause, we evaluated changes in birthweight distributions (BDs) and birthweight-specific mortality rates (BSMRs) among black and white infants born in the United States between 1983 and 1991. METHODS: Using national linked birth and death certificate data, we limited analyses to singleton births that occurred in the United States to resident, non-Hispanic black and white women. Birthweight data were analyzed in 500 g increments. The black-white gap was partitioned into deaths due to differences in BDs and BSMRs. RESULTS: The black-white infant mortality rate ratio increased from 2.1 in 1983 to 2.4 in 1991. Decreases in BSMRs among infants weighing from 500 to 2499 g occurred in both groups but were smaller among black than white infants; consequently, the percentage of excess deaths to black infants due to differences in BSMRs almost doubled during the study period, from 6.5% to 11.9%. Rates of very low birthweight (VLBW, < 1,500 g) increased for black infants, but the BD for white infants changed little. Although about 90% of the excess deaths to black infants resulted from differences in BDs, the changes in BDs had a minimal effect on the widening infant mortality gap. CONCLUSIONS: A significant reduction in the black-white infant mortality gap will require a reduction in VLBW and low birthweight (LBW, < 2,500 g). To keep the gap from growing, we must also investigate why decreases in BSMRs were smaller among black than white infants between 1983 and 1991.

Black or African American↗

PubMed1998

Cause-specific trends in neonatal mortality among black and white infants, United States, 1980-1995.

OBJECTIVE: Although neonatal mortality has been declining more rapidly than postneonatal mortality in recent decades, neonatal mortality continues to account for close to two-thirds of all infant deaths. This report uses U.S. vital statistics data to describe national trends in the major causes of neonatal mortality among black and white infants from 1980 to 1995. METHODS: Mortality rates were estimated as the number of deaths due to each cause (based on International Classification of Diseases, 9th Revision, codes) divided by the number of live births during the same time period. Linear regression models and smoothed rates were used to describe trends. RESULTS: During the study period, neonatal mortality declined 4.0% per year for white infants and 2.2% per year for black infants, and the black-white gap increased from 2.0 to 2.4. By 1995, disorders relating to short gestation and low birth weight were the number one cause of neonatal death for black infants and the number two cause for white infants, had the highest black-white disparity (4.6, up from 3.3 in 1980), and accounted for almost 40% of excess deaths to black infants (up from 24% in 1980). Congenital anomalies were the number two cause of neonatal death for black infants and the highest ranked cause for white infants in 1995, and it is the only cause for which there was not a substantial excess risk to black infants. CONCLUSIONS: Large declines in neonatal mortality have been achieved in recent years, but not in the black-white gap, which has increased. Declines were slower for black than white infants overall and for almost all causes. Prevention of preterm delivery and low birth weight continue to be a priority for reducing neonatal mortality, particularly among black infants. Although congenital anomalies do not contribute substantially to the black-white gap, their diagnosis, treatment, and prevention is critical to reducing overall neonatal mortality.

Black People↗

PubMed1997

A critical review of the relationship between gestational weight gain and preterm delivery.

OBJECTIVE: To review the relationship between gestational weight gain and preterm delivery. DATA SOURCES: We identified published studies through Medline searches (for the period 1980-1996), and we reviewed bibliographies from published articles. METHODS OF STUDY SELECTION: We excluded non-English-language articles and articles that used total weight gain, unadjusted for gestational age. Thirteen articles were identified for review. TABULATION, INTEGRATION AND RESULTS: Eleven of the 13 studies reported a significant association between maternal weight gain and risk of preterm delivery, and most reported that inadequate rate of maternal weight gain was associated with an increased risk (approximately 50-100%) of preterm delivery. Studies examining pattern of gain noted that a low rate of gain during the latter part of pregnancy (but not early pregnancy) was associated with an increased risk of preterm delivery (also approximately 50-100%). The studies' findings were relatively consistent, despite the use of diverse samples, study designs, and analytic strategies. CONCLUSION: The evidence suggests that a lower rate of weight gain during pregnancy is associated with an increased risk of preterm delivery, and that a slow rate of gain during the latter part of pregnancy may be particularly important. To improve our understanding of the mechanisms of these relationships, future studies should examine pattern of gain; they should stratify analyses on the different subtypes of preterm delivery and provide more detailed descriptions of methods for assessing gestational duration.

Delivery, Obstetric↗

PubMed1990

Effects of dietary n-3 and n-6 polyunsaturated fatty acids on macrophage phospholipid classes and subclasses.

This study examined the effects of n-3 and n-6 polyunsaturated fatty acid alimentation on murine peritoneal macrophage phospholipids. Mice were fed complete diets supplemented with either corn oil predominantly containing 18:2n-6, borage oil containing 18:2n-6 and 18:3n-6, fish/corn oil mixture containing 18:2n-6, 20:5n-3 and 22:6n-3, or fish/borage oil mixture containing 18:2n-6, 18:3n-6, 20:5n-3 and 22:6n-3. After two weeks, the fatty acid levels of glycerophosphoserines (GPS), glycerophosphoinositols (GPI), sphingomyelin (SPH), and of the glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE) phospholipid subclasses were determined. We found that mouse peritoneal macrophage GPC contain primarily 1-O-alkyl-2-acyl (range for the dietary groups, 24.6-30.5 mol %) and 1,2-diacyl (63.2-67.2 mol %), and that GPE contains 1-O-alk-1'-enyl-2-acyl (40.9-47.4 mol %) and 1,2-diacyl (44.2-51.2 mol %) subclasses. In general, fish oil feeding increased macrophage 20:5n-3, 22:5n-3 and 22:6n-3 levels while simultaneously reducing 20:4n-6 in GPS, GPI, GPE and GPC subclasses except for 1-O-alk-1'-enyl-2-acyl GPC. Administration of 18:3n-6 rich diets (borage and fish/borage mixture) resulted in the accumulation of 20:3n-6 (2-carbon elongation product of 18:3n-6) in most phospholipids. In general, the novel combination of dietary 18:3n-6 and n-3 PUFA produced the highest 20:3n-6/20:4n-6 phospholipid fatty acid ratios. This study demonstrates that marked differences in the responses of macrophage phospholipid classes and subclasses exist following dietary manipulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Effect of dietary blackcurrant seed oil on mouse macrophage subclasses of choline and ethanolamine glycerophospholipids.

There have been reports that dietary gamma-linolenic acid [18:3(n-6)] and alpha-linolenic acid [18:3(n-3)] are capable of regulating cellular eicosanoid biosynthesis and inflammation. Because the eicosanoid cascade is regulated in part by the distribution of arachidonic acid [20:4(n-6)] among phospholipid subclasses, the effects of feeding blackcurrant seed oil [containing 18:3(n-6) and 18:3(n-3)] on the fatty acid composition of diacyl, alkylacyl and alkenylacyl subclasses of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were studied in mouse peritoneal macrophages. After 4 wk of dietary treatment, the relative distribution (mol %) of macrophage phospholipid classes and subclasses was not altered in animals fed blackcurrant seed oil relative to those fed corn oil [containing linoleic acid, 18:2(n-6)]. Macrophages from blackcurrant seed oil-fed animals had reduced levels of PC diacyl 18:3(n-6), 18:3(n-3), 20:3(n-6), 22:5(n-3), and alkylacyl 20:3(n-6), 22:5(n-3) and 22:6(n-3). In general, dietary blackcurrant treatment produced fatty acid alterations in PE subclasses that were similar to those in PC. A major exception, however, was the reduction in 20:4(n-6) levels in all PE subclasses, whereas no effect in PC subclass 20:4(n-6) levels was noted. These findings indicate i) that pronounced differences in the polyunsaturated fatty acid (PUFA) compositions of macrophage PC and PE subclasses exist following dietary fat manipulation and ii) that 18:3(n-6) and 18:3(n-3) feeding can increase potential anti-flammatory precursor levels of 20:3(n-6) and (n-3) PUFA in the macrophage.

Animals↗

PubMedDate not supplied

Assessing combined chemical exposures as risk factors for neural tube defects.

Many studies have investigated whether chemical exposures early in pregnancy increase risks to women of delivering offspring with congenital anomalies. We investigated whether periconceptional exposures to chemicals in combination increased risks to women of having neural tube defect (NTD)-affected pregnancies. Women were asked about occupational tasks performed during the periconceptional period. These tasks were assigned by an industrial hygienist to a priori defined exposure categories. The exposure categories included 74 chemical groups. Two population-based case control studies were analyzed. Information on tasks was obtained from mothers of 538 NTD cases and their 539 controls in one study, and mothers of 265 NTD cases and 481 controls from another study. We used data from the first study to identify clues. Specifically, we estimated NTD risks for maternal occupational exposures to all possible pairs, triplets, and quadruplets of 74 chemical groups. Chemical combinations revealing elevated NTD risks in these "clue generation" analyses were then investigated in the second population-based case-control study for their contribution to risk of NTDs. We computed odds ratios for each of the total 192,374 possible comparisons and identified all combinations that produced odds ratios of 5 or more. A 5-fold elevated risk criterion revealed 53 combinations. These 53 reflected various combinations of exposures exclusive to 12 of 74 chemical groups. Analyses of data from the second study did not identify odds ratios of 2.0 or greater for maternal exposures to the 12 chemical groups that resulted in 5-fold elevated risks in the first study. Despite the use of a labor-intensive method to categorize exposures, we were unable to substantiate clues associated with combined chemical exposures identified in one large case-control study as NTD risk factors in a second case-control study.

Adult↗