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Allen A Mitchell

Publications and source records attributed to Allen A Mitchell.

At least 37 records · Page 2Linked to original sources
PubMed2004

Vasoactive exposures, vascular events, and hemifacial microsomia.

BACKGROUND: Based on experimental evidence and clinical observations, hemifacial microsomia (HFM) is one of several structural anomalies that are postulated to result from vascular disruption. We collected data in a case-control study to identify whether vasoactive exposures or vascular events during early pregnancy affect the risk of HFM. METHODS: Cases with a diagnosis of HFM were identified at craniofacial centers in 26 cities across the United States and Canada, from 1996 to 2002. Controls were matched to cases by age and pediatrician practice. Mothers of 230 cases and 678 controls were interviewed about pregnancy events and exposures. Case and control mothers were compared for early pregnancy use of vasoactive medications, cigarettes, and alcohol; singleton or multiple gestation; and diabetes, hypertension, or vaginal bleeding in the first half of pregnancy. RESULTS: Odds ratios (ORs) were significantly increased for vasoactive mediation use (OR, 1.9 overall; OR, 4.2 among smokers), multiple gestations (OR, 10.5), and diabetes (OR, 6.0). Vaginal bleeding in the second trimester and heavy alcohol intake were associated with increased risks, but the estimates were based on small numbers and, therefore, are unstable. No associations were observed for cigarette smoking without vasoactive medication use, hypertension, and vaginal bleeding in the first trimester. CONCLUSIONS: The increased risks of HFM associated with vasoactive medication use, multiple gestations, diabetes, and second trimester vaginal bleeding appear collectively to support the hypothesis that vascular disruption is one etiology for HFM, because each of these factors is related to effects on blood vessels.

Alcohol Drinking↗
PubMed2004

Racial/ethnic disparities in the diagnosis of otitis media in infancy.

OBJECTIVE: Otitis media (OM) is an extremely common pediatric diagnosis. Several risk factors have been associated with OM, but the relationship between OM and race/ethnicity remains controversial. We sought to define the relationship between OM diagnosis and race/ethnicity in infants. METHODS: By multivariable logistic regression, we evaluated the association between OM diagnosis and race/ethnicity in 11,349 non-low-birthweight infants who were participants in a prospective cohort study of infant care practices. RESULTS: As in previous studies, breastfeeding was associated with a decreased risk of OM diagnosis while other factors were independently associated with a substantially increased risk of OM diagnosis: out-of-home daycare, multiple children living in the home, and mother's multiparity. Daycare was associated with a "dose effect" in that the risk of OM diagnosis increased with an increasing number of children in the daycare. While the crude analysis suggested little relation of OM diagnosis and race/ethnicity, the association was confounded by several covariates including maternal marital status, number of children living in the home, breastfeeding status, and maternal age. After adjustment for relevant confounders, Black (OR 0.74; 95% CI 0.61-0.89) and Asian infants (OR 0.77; 95% CI 0.57-1.0]) were less likely to be diagnosed with OM than White infants. CONCLUSIONS: This large prospective study confirms previous risk factors for OM and demonstrates a strong "dose effect" of the size of daycare centers on OM. The study also demonstrates that the association between race/ethnicity and OM diagnosis is confounded by social factors. After adjusting for such factors, Black and Asian infants are less likely to be diagnosed with OM than White infants. The reason for this racial disparity remains unknown.

Black or African American↗
PubMed2004

Frequency of bed sharing and its relationship to breastfeeding.

Bed sharing has been promoted as facilitating breastfeeding but also may increase risks for sudden, unexpected infant deaths. This prospective cohort study was performed to determine the prevalence of adult and infant bed sharing and its association with maternal and infant characteristics. Demographic data were collected from 10,355 infant-mother pairs at birth hospitals in Eastern Massachusetts and Northwest Ohio, and follow-up data were collected at 1, 3, and 6 months by questionnaire. Associations with bed sharing were estimated using odds ratios and 95% confidence intervals from multiple logistic regression models while adjusting for confounding variables. At 1, 3, and 6 months, 22%, 14%, and 13% of infant-mother pairs shared a bed, respectively. On multivariate analysis, race/ethnicity and breastfeeding seemed to have the strongest association with bed sharing. These factors need to be considered in any comprehensive risk to benefit analysis of bed sharing.

Adolescent↗
PubMed2004

Demographic and reproductive factors associated with hemifacial microsomia.

OBJECTIVE: To identify demographic and reproductive risk factors for hemifacial microsomia in offspring. DESIGN: In a case-control study, maternal interviews were conducted within 3 years after delivery. Cases with hemifacial microsomia were ascertained from craniofacial centers in 26 cities in the United States and Canada. Controls were patients of the cases' pediatricians. Two hundred thirty-nine cases were compared with 854 controls. Odds ratios for various infant and maternal factors were estimated. RESULTS: Cases had lower birth weights, were more often male or a twin, and had more relatives with craniofacial malformations or hearing loss than controls. Case mothers had lower family incomes, had a lower body mass index, had more vaginal bleeding in the second trimester, and were more likely to have had a spontaneous abortion in a previous pregnancy. CONCLUSIONS: Nonmodifiable factors (age and parity) were not associated with hemifacial microsomia risk. Factors that are related to poverty (low family income, late recognition of pregnancy, and low body mass index) are associated with an increase in risk. High risk estimates for multiple pregnancies and second-trimester vaginal bleeding suggest a vascular etiology.

Case-Control Studies↗
PubMed2003

Case-crossover and case-time-control designs in birth defects epidemiology.

The case-crossover and the case-time-control designs can be used to evaluate the effect of intermittent exposures on the risk of acute events. To explore how birth defects epidemiology could benefit from these approaches, the authors compared them with a traditional case-control study design that evaluated the association between use of folic acid antagonists during the second and third pregnancy months and the risk of cardiovascular defects. Among 3,870 cases and 8,387 control infants in the Slone Epidemiology Center Birth Defects Study (1976-1998), the odds ratio was 2.3 (95% confidence interval (CI): 1.4, 3.9). The case-crossover approach compared folic acid antagonist use between the 2-month embryologically sensitive period (case window) and the 2 months preceding the last menstrual period (control window) among mothers of case infants (odds ratio = 1.0, 95% CI: 0.5, 2.0). Although it controls between-person confounding and avoids issues of control selection, this design may be biased by time trends of exposure prevalence during pregnancy. The case-time-control design, which adjusts for exposure time trends under certain assumptions, yielded an odds ratio of 2.9 (95% CI: 1.2, 7.2), but it requires controls. In the presence of gestational time trends of exposure, the new designs do not offer clear advantages over the case-control design.

Case-Control Studies↗
PubMed2003

Infant sleep position and associated health outcomes.

BACKGROUND: The incidence of sudden infant death syndrome has decreased in the United States as the percentage of infants sleeping prone has decreased, but persisting concerns about the safety of supine sleeping likely contribute to prone sleeping prevalence rates that remain higher than 10%. OBJECTIVE: To document health outcomes in infants aged 1 to 6 months in relation to sleep position. DESIGN: Prospective cohort study. SETTING: Massachusetts and Ohio, from February 21, 1995, to December 31, 1998. STUDY PARTICIPANTS: A total of 3733 infants with consistent sleep positions at ages 1, 3, and 6 months. MAIN OUTCOME MEASURES: Descriptive statistics and multiple logistic regression analysis relating sleep position at each follow-up age to symptoms in the prior week (fever, cough, wheezing, stuffy nose, trouble breathing or sleeping, diarrhea, vomiting, or spitting up) and outpatient visits in the prior month (ear infection, breathing problem, vomiting, spitting up, colic, seizure, accident, or injury). RESULTS: No symptoms or outpatient visits were significantly more common among infants sleeping on the side or supine than in infants sleeping prone, and 3 symptoms were less common: (1) fever at 1 month in infants sleeping in the supine (adjusted odds ratio [OR], 0.56; 95% confidence interval [CI], 0.34-0.93) and side positions (OR, 0.48; 95% CI, 0.28-0.82); (2) stuffy nose at 6 months in the supine (OR, 0.74; 95% CI, 0.61-0.89) and side positions (OR, 0.82; 95% CI, 0.68-0.99); and (3) trouble sleeping at 6 months in the supine (OR, 0.57; 95% CI, 0.44-0.73) and side positions (OR, 0.69; 95% CI, 0.53-0.89). Also, outpatient visits for ear infections were less common at 3 and 6 months in infants sleeping in the supine position (OR, 0.64; 95% CI, 0.46-0.88; and OR, 0.73; 95% CI, 0.58-0.92, respectively) and at 3 months in the side position (OR, 0.68; 95% CI, 0.49-0.96). CONCLUSIONS: No identified symptom or illness was significantly increased among nonprone sleepers during the first 6 months of life. These reassuring results may contribute to increased use of the supine position for infant sleeping.

Adolescent↗
PubMed2003

Epidemiologic analysis of maternal factors and amniotic band defects.

BACKGROUND: The group of defects identified as amniotic bands includes amnion rupture sequence (ARS) and body wall complex (BWC). Little is known about risk factors for either ARS or BWC, except that maternal age has been shown to affect risk inversely. METHODS: The present analysis used data collected from 1976 to 1998 as part of an ongoing case control study of birth defects in the metropolitan areas of Boston, Philadelphia, and Toronto. There were 73 cases with ARS and 11 cases with BWC. ARS cases were further subdivided according to affected structures: there were 53 with only limbs affected (ARS-L) and 20 with nonlimb defects with or without limb defects (ARS-NL). The control group comprised 12,227 subjects with other major malformations. Mothers were interviewed within 6 months of delivery about demographic, reproductive, medical, and behavioral factors. RESULTS: Multivariate adjusted odds ratios for BWC were increased more than threefold for maternal age < 25 years and maternal education < 12 years, but neither estimate was statistically significant. Corresponding estimates for ARS-L and ARS-NL ranged from 13 to 1.5 and also were not statistically significant. Cases were less likely to be white non-Hispanic than controls and the odds ratio for ARS-NL excluded the null. The multivariate adjusted odds ratio (MVOR) for unplanned pregnancy and BWC was 1.9 (95% confidence interval, 0.5-6.7) compared to 1.2 and 1.0 for ARS-L and ARS-NL, respectively. Neither parity nor maternal smoking was associated with any case group. The MVORs for first trimester acetaminophen use in relation to ARS-L and ARS-NL risks were 2.1 (1.1-3.9) and 3.4 (1.1-10.3), respectively. Such use was less common among BWC cases (MVOR was 0.4; 0.1-1.4). CONCLUSIONS: Risk estimates tended to be similar for ARS-L and ARS-NL cases but different for BWC cases, suggesting different etiologies. These data suggest that young maternal age, low maternal education, unplanned pregnancy, and non-white/non-Hispanic race/ethnicity might increase the risk of BWC in offspring. Inceased risks for acetaminophen use should be interpreted with caution because they may be confounded by indication for use.

Acetaminophen↗
PubMed2003

Association between prepregnancy maternal body mass index and the risk of having an infant with a congenital diaphragmatic hernia.

BACKGROUND: A previous study observed that women who are underweight prior to conception were significantly more likely to have infants affected by congenital diaphragmatic hernia (CDH). The objective of the current study was to examine the association between maternal body mass index and the risk of a CDH-affected offspring based on a larger number of cases of CDH. METHODS: A case control study was conducted using data collected by the Boston University Slone Epidemiology Center Birth Defects Study, which identifies infants with major malformations who are born in the metropolitan area surrounding Boston, Massachusetts; Philadelphia, Pennsylvania; and Toronto, Ontario, Canada. Control infants were selected from infants without malformations who were born in the same areas. The study included 85 cases of CDH and 655 controls delivered between 1993 and 1997. RESULTS: After adjustment for maternal education and maternal age, we observed that women who were thin or underweight for their height (body mass index < or = 19.0 kg/m2) had an increased risk of having an infant with isolated CDH (OR = 1.9; 95% CI = 0.92-4.1), but no increase in the risk of having a CDH infant with multiple defects (OR = 0.86; 95% CI = 0.29-2.6) compared with all other women. CONCLUSIONS: Although our finding for isolated CDH was not statistically significant (P = 0.08), it suggests that the offspring of thin or underweight women may have an increased risk of isolated CDH. This finding requires confirmation. If it is confirmed, further research on factors associated with being underweight should be explored such as diet, exercise, and use of drugs.

Body Mass Index↗
PubMed2003

Low maternal alcohol consumption during pregnancy and oral clefts in offspring: the Slone Birth Defects Study.

BACKGROUND: The association between maternal alcohol consumption during pregnancy and oral clefts in offspring remains unclear. We studied this relation in a case-control surveillance study of birth defects. METHODS: From 1983 to 1997, we recruited 5956 study subjects from greater Boston, Philadelphia, Toronto, and parts of Iowa. The cases were liveborn infants with cleft palate alone (CP; n = 205), cleft lip and palate (CLP; n = 383), cleft lip alone (CL; n = 259), or Pierre-Robin sequence (n = 65). The controls (n = 4272) were infants who had no oral clefts but had one or more of the following defects: malformations of the digestive tract, reproductive organs, abdominal wall, and respiratory tract; chromosomal anomalies; inguinal hernia; tumors; and Mendelian inherited disorders. Based on maternal reports of alcohol consumption during the first 4 months of pregnancy, we derived average weekly consumption, average number of drinks per drinking day, and the maximum number of drinks consumed in a given day. The mothers also provided data on potential confounding or modifying variables, such as vitamin supplement use. RESULTS: There was no relation between maternal alcohol consumption during pregnancy and CL or CP. The odds ratios (ORs) for cleft lip with or without palate (CL/P) were 1.0, 1.1, and 0.9 in women who consumed <1.0, 1.0-2.9, and 3.0 + drinks per week, respectively. These findings did not change when we considered possible modifying effects of vitamin supplement use. CONCLUSIONS: Our findings do not support an association between oral clefts and a low level of alcohol consumption.

Adult↗
PubMed2003

Secular changes in sleep position during infancy: 1995-1998.

OBJECTIVE: Prone sleeping among infants has been associated with an increased risk of sudden infant death syndrome. The objective of this study was to compare factors associated with sleep position in 1995-1996 and 1997-1998 and to assess secular trends in use of prone infant sleep position from 1995 through 1998 among families stratified by race and education. METHODS: A prospective cohort study was conducted in eastern Massachusetts and northwest Ohio of 12 029 mothers of infants who weighed > or =2500 g at birth. Descriptive statistics and multivariate odds ratios were used to relate maternal and infant characteristics to prone and supine sleeping. RESULTS: A total of 14 206 mothers (25% of those eligible) were enrolled. A total of 12 029 mothers (85% of enrolled) responded to the 1-month and 11 552 mothers (81% of enrolled) responded to the 3-month follow-up questionnaire. A decline in use of the prone sleep position and increase in use of the supine position was observed during the 4 years of the study. Factors associated with prone and supine sleep position were similar in 1995-1996 and 1997-1998. In 1997-1998, use of prone sleeping at 1 month of age reached the goal of < or =10% only among infants of white and Asian women, married women, women who were older than 25 years, women who were college graduates, and women with incomes >$55 000 per year. At 3 months of age, however, prone sleeping increased to 12% to 17% in these groups. These same groups were most likely to use the supine position; 38% to 45% were supine at 1 month, increasing to 56% to 64% by 3 months of age. However, as of the end of 1998, approximately 27% of infants of non-college-educated black and Hispanic mothers were placed to sleep in the prone position and only 20% to 30% were being placed to sleep in the supine position at 3 months of age. CONCLUSIONS: Recommendations to avoid prone sleep position and especially the recommendation that supine sleep position is preferred have not been effectively delivered to black and Hispanic families and to families of low-income and less than a college education.

Chi-Square Distribution↗
PubMed2003

Sleep position of low birth weight infants.

OBJECTIVES: To describe sleep positions among low birth weight infants, variations in sleep position according to birth weight, and changes in sleep position over time. To analyze risk factors and influences associated with prone sleep. DESIGN: Prospective cohort study. SETTING: Massachusetts and Ohio, 1995-1998. STUDY PARTICIPANTS: Mothers of 907 low birth weight infants. RESULTS: At 1, 3, and 6 months after hospital discharge, the prevalence of prone sleeping was 15.5%, 26.8%, and 28.3%, respectively. The corresponding rates for supine sleeping were 23.8%, 37.9%, and 50.2% and for side sleeping were 57.3%, 32.4%, and 20.6%. Very low birth weight (VLBW) infants (<1500 g) were most likely to be placed in the prone position. From 1995 through 1998, prone sleeping 1 month after hospital discharge declined among all low birth weight infants from 19.9% to 11.4%; among VLBW infants, the decline in prone sleeping was replaced almost entirely by an increase in side sleeping, whereas in larger low birth weight infants, it was replaced primarily by supine sleeping. Among mothers who placed their infants to sleep in nonprone positions, professional medical advice was cited most frequently as the most influential reason, whereas among mothers of prone-sleeping infants, the infant's preference was cited most frequently. However, mothers of prone-sleeping VLBW infants also frequently cited the influence of medical professionals and nursery practices as most important in the choice of sleeping position. The factors most strongly associated with prone sleeping were single marital status (odds ratio [OR]: 3.0; 95% confidence interval [CI]: 1.5-6.2), black race (OR: 2.6; 95% CI: 1.5-4.5), birth weight <1500 g (OR: 2.4; 95% CI: 1.3-4.3), and multiparity (OR: 2.1, 95% CI: 1.2-3.5). CONCLUSIONS: Prone sleep decreased among low birth weight infants from 1995 to 1998. However, VLBW infants, who are at very high risk for sudden infant death syndrome, are more likely to sleep prone than larger low birth weight infants.

Birth Weight↗
PubMed2003

Association of vasoconstrictive exposures with risks of gastroschisis and small intestinal atresia.

BACKGROUND: Gastroschisis and small intestinal atresia are congenital anomalies that may arise from vascular disruption. It is hypothesized that maternal exposure to cocaine, amphetamines, decongestants and nicotine, all of which have vasoconstrictive actions, can contribute to these defects. The present study examined risks of gastroschisis and small intestinal atresia associated with combined exposure to vasoconstrictive drugs and cigarette smoking. METHODS: This was a retrospective study conducted from 1995 to 1999 in 15 cities across the United States and Canada. Mothers of 205 gastroschisis cases, 127 small intestinal atresia cases, 381 malformed controls and 416 nonmalformed controls were interviewed within 6 months of delivery. RESULTS: Reported vasoconstrictive drugs included pseudoephedrine, phenylpropanolamine, ephedrine and methylenedioxymethamphetamine. Combined exposure to vasoconstrictive drugs and cigarette smoking in the first 2.5 months of pregnancy was reported by 9% of gastroschisis cases, 9% of small intestinal atresia cases and 4% of controls. Multivariate-adjusted odds ratios, controlling for the effects of age, education, income, other drug use and alcohol intake, were 2.1 (95% confidence interval = 1.0-4.4) for gastroschisis and 2.8 (1.1-6.9) for small intestinal atresia. Risks of each defect increased with increasing level of cigarettes (P for trend = 0.019 and 0.012, respectively). Vasoconstrictive drug use among smokers of 20 or more cigarettes a day increased gastroschisis risk 3.6-fold (1.3-10.3) and small intestinal atresia risk 4.2-fold (1.1-16.2). CONCLUSIONS: These findings provide further evidence of vascular disruption as an etiology for gastroschisis and small intestinal atresia.

Adult↗
PubMed2002

Risk of gestational hypertension in relation to folic acid supplementation during pregnancy.

The authors investigated the association between folic acid supplementation and gestational hypertension. The study population included women with nonmalformed infants in the United States and Canada who were participating in the Slone Epidemiology Center Birth Defects Study between 1993 and 2000. Women were interviewed within 6 months after delivery about sociodemographic and medical factors, the occurrence of hypertension with or without preeclampsia, and multivitamin use in pregnancy. Relative risks, adjusted for weight, parity, twin pregnancy, diabetes, smoking, education, and family income, were estimated using Cox regression models. Of 2,100 women, 204 (9.7%) reported gestational hypertension (onset after the 20th week of gestation). The multivariate-adjusted relative risk of developing gestational hypertension during the month after folic acid supplementation, compared with not using folic acid during that same month, was 0.55 (95% confidence interval: 0.39, 0.79). This finding suggests that folic acid-containing multivitamins may reduce the risk of gestational hypertension.

Adult↗
PubMed2002

Recent patterns of medication use in the ambulatory adult population of the United States: the Slone survey.

CONTEXT: Data on the range of prescription and over-the-counter drug use in the United States are not available. OBJECTIVE: To provide recent population-based information on use of all medications, including prescription and over-the-counter drugs, vitamins and minerals, and herbal preparations/natural supplements in the United States. DESIGN, SETTING, AND PARTICIPANTS: Ongoing telephone survey of a random sample of the noninstitutionalized US population in the 48 continental states and the District of Columbia; data analyzed here were collected from February 1998 through December 1999. MAIN OUTCOME MEASURE: Use of medications, by type, during the preceding week, compared by demographic characteristics. RESULTS: Among 2590 participants aged at least 18 years, 81% used at least 1 medication in the preceding week; 50% took at least 1 prescription drug; and 7% took 5 or more. The highest overall prevalence of medication use was among women aged at least 65 years, of whom 12% took at least 10 medications and 23% took at least 5 prescription drugs. Herbals/supplements were taken by 14% of the population. Among prescription drug users, 16% also took an herbal/supplement; the rate of concurrent use was highest for fluoxetine users, at 22%. Reasons for drug use varied widely, with hypertension and headache mentioned most often (9% for each). Vitamins/minerals were frequently used for nonspecific reasons such as "health" (35%); herbals/supplements were also most commonly used for "health" (16%). CONCLUSIONS: In any given week, most US adults take at least 1 medication, and many take multiple agents. The substantial overlap between use of prescription medications and herbals/supplements raises concern about unintended interactions. Documentation of usage patterns can provide a basis for improving the safety of medication use.

Adult↗