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Biomedical subjects

Allen A Mitchell

Publications and source records attributed to Allen A Mitchell.

At least 19 recordsLinked to original sources
PubMed2006

Tolerability of oral xylitol solution in young children: implications for otitis media prophylaxis.

OBJECTIVE: Xylitol, given as 2g orally five times-a-day, significantly reduces the incidence of acute otitis media (AOM) in children. A less frequent dosing schedule, if tolerable and efficacious, would promote the more widespread use of this treatment. We sought to determine the tolerability and acceptability in young children of oral xylitol solution at doses of 5g three times-a-day (TID) and 7.5g once daily (QD). METHODS: The study was a 3-month randomized placebo-controlled trial of the tolerability and acceptability of oral xylitol solution in 120 children 6-36 months of age performed in the SCOR Network. RESULTS: Study withdrawals and unscheduled medical visits for gastrointestinal complaints did not differ significantly among the study groups. The proportions of subjects in the xylitol TID group who experienced excessive gas or diarrhea at months 1, 2, and 3 were 22.7%, 10.0%, and 14.3%, respectively, and in the xylitol QD group were 27.3%, 17.4%, and 14.3%, respectively, and these did not differ from the placebo groups. The proportions who accepted the study solution easily or with only minor difficulty at 1, 2, and 3 months in the xylitol TID group were 77.3%, 90.0%, and 90.5% and in the xylitol QD group, 77.3%, 82.6%, and 90.5%, respectively. CONCLUSIONS: Oral xylitol solution at dosages of 5g TID and 7.5g QD is well-tolerated by young children. Given the potential for xylitol as a safe, inexpensive option for AOM prophylaxis, clinical trials using these dosages of xylitol can be conducted.

Administration, Oral↗
PubMed2006

Selective serotonin-reuptake inhibitors and risk of persistent pulmonary hypertension of the newborn.

BACKGROUND: Persistent pulmonary hypertension of the newborn (PPHN) is associated with substantial infant mortality and morbidity. A previous cohort study suggested a possible association between maternal use of the selective serotonin-reuptake inhibitor (SSRI) fluoxetine late in the third trimester of pregnancy and the risk of PPHN in the infant. We performed a case-control study to assess whether PPHN is associated with exposure to SSRIs during late pregnancy. METHODS: Between 1998 and 2003, we enrolled 377 women whose infants had PPHN and 836 matched control women and their infants. Maternal interviews were conducted by nurses, who were blinded to the study hypothesis, regarding medication use in pregnancy and potential confounders, including demographic variables and health history. RESULTS: Fourteen infants with PPHN had been exposed to an SSRI after the completion of the 20th week of gestation, as compared with six control infants (adjusted odds ratio, 6.1; 95 percent confidence interval, 2.2 to 16.8). In contrast, neither the use of SSRIs before the 20th week of gestation nor the use of non-SSRI antidepressant drugs at any time during pregnancy was associated with an increased risk of PPHN. CONCLUSIONS: These data support an association between the maternal use of SSRIs in late pregnancy and PPHN in the offspring; further study of this association is warranted. These findings should be taken into account in decisions as to whether to continue the use of SSRIs during pregnancy.

Antidepressive Agents↗
PubMed2006

Can folic acid protect against congenital heart defects in Down syndrome?

BACKGROUND: Several studies have suggested a protective effect of folic acid (FA) on congenital heart anomalies. Down syndrome (DS) infants are known to have a high frequency of heart anomalies. Not all children with DS suffer from heart anomalies, which raises the question whether maternal factors might affect the risk of these anomalies. Our objectives were to investigate whether first-trimester FA use protects against heart anomalies among DS children. METHODS: Women with liveborn DS children participating in the Slone Epidemiology Center Birth Defects Study between 1976 and 1997 were included. We performed case-control analyses using DS, with heart anomalies as cases and DS, without heart anomalies as controls. Subanalyses were performed for defects that have been associated with FA in non-DS populations (conotruncal, ventricular septal [VSD]) and for those that are associated with DS (ostium secundum type atrial septal defects [ASD] and endocardial cushion defects [ECD]). Exposure was defined as the use of any FA-containing product for an average of at least 4 days per week during the first 12 weeks of pregnancy, whereas no exposure was defined as no use of FA in these 12 weeks. RESULTS: Of the 223 cases, 110 (49%) were exposed versus 84 (46%) of the 184 controls. After adjustment for possible confounders, no protective effect of FA was found on heart anomalies overall (OR 0.95, 95% CI: 0.61-1.47) nor separately for conotruncal defects, VSDs, ASDs, or ECDs. CONCLUSIONS: Our study does not show a protective effect of FA on heart anomalies among infants with DS.

Dietary Supplements↗
PubMed2006

Diarrhea in American infants and young children in the community setting: incidence, clinical presentation and microbiology.

OBJECTIVE: The characteristics and microbiology of the full spectrum of pediatric diarrhea occurring in the U.S. community setting are not well-understood. METHODS: Six-month prospective cohort study of 604 healthy 6- to 36-month-old children recruited by the Slone Center Office-based Research Network. RESULTS: The incidence of parent-defined diarrhea was 2.2 episodes per person-year. The median duration of diarrhea was 2 days with a median of 6 stools per episode. Outpatient visits and hospitalization were prompted by 9.7 and 0.3% of episodes, respectively. The most common microorganisms identified in healthy baseline stools were atypical enteropathogenic Escherichia coli (12.2%), enteroaggregative Escherichia coli (3.7%), Clostridium difficile (3.5%) and Clostridium perfringens (2.9%), and each of these was no more common in diarrhea stools. In contrast, all of the viruses analyzed were more prevalent in diarrhea specimens than in baseline specimens: enteric adenovirus (5.7% diarrhea versus 1.4% baseline), rotavirus (5.2% versus 1.4%), astrovirus (3.5% versus 1.4%), Sapporo-like virus (3.0% versus 0.8%) and norovirus (1.9% versus 0.8%). A likely pathogen was detected in 20.6% of diarrhea specimens. Vomiting and > or =16 stools in an episode were predictive of isolating a pathogen from the stool, each with a relative risk of approximately 2. CONCLUSIONS: Healthy young children in this study experienced more than 2 cases of diarrhea per person-year, but most were brief and do not require medical attention. Although most diarrhea-associated pathogens were viruses, no likely pathogen was found in almost 80% of cases; possible etiologies for these cases include currently unknown gastrointestinal infections, nongastrointestinal illnesses and dietary/environmental factors.

Adenoviruses, Human↗
PubMed2006

Knowledge and practices relating to the 2004 acute otitis media clinical practice guideline: a survey of practicing physicians.

OBJECTIVE: To identify primary care physicians' familiarity with the 2004 acute otitis media (AOM) clinical practice guideline and to compare their practices with its recommendations. DESIGN: Mail survey October through December 2004 to all active physician members of the Slone Center Office-based Research Network, a national, practice-based, pediatric research network. RESULTS: The response rate was 276 of 469 (58.8%). Overall, 90.5% had read the guideline or summaries of it. Pneumatic otoscopy was always used by 16.2%, used half the time or more by 23.1%, used less than half the time by 34.6% and never used by 26.2%. Observation is considered a reasonable option for some AOM cases by 88.0% and, over the previous 3 months, these physicians used observation a median of 10% of the time (25th and 75th percentiles, 5% and 25%, respectively). In terms of concern that the observation option may increase AOM complications, 75.6% were not at all or only slightly concerned; 24.4% were moderately or very concerned. In general, these physicians have altered their antibiotic prescribing practices for AOM towards the guideline's recommendations since its publication. However, antibiotic choices deviated most widely from the guideline in cases of AOM with severe illness, where only 17.9% follow the recommendation for high-dose amoxicillin-clavulanate, and in cases of children who fail treatment with amoxicillin-clavulanate, where only 27.7% favor the recommended intramuscular ceftriaxone. CONCLUSIONS: Most physicians in this survey are familiar with the AOM guideline, but many do not follow its diagnostic and antibiotic recommendations. Observation for selected cases is acceptable to most of these physicians and is currently used in a small proportion of cases.

Acute Disease↗
PubMed2006

Characteristics of persistent diarrhea in a community-based cohort of young US children.

OBJECTIVE: The objective of the study was to define the characteristics and microbiology of persistent diarrhea (PD) in US children. METHODS: Six-month prospective cohort study of a convenience sample of 604 healthy 6- to 36-month-old children recruited by the Slone Center Office-based Research Network. RESULTS: Of 611 diarrhea episodes, 50 (8.2%) lasted < or = 14 days. The incidence of PD was 0.18 episodes per person-year, and the median duration of episodes was 22.0 days (range, 14-64 days). PD episodes were more likely than acute episodes to result in a medical visit (28.0% vs 8.2%; P = 0.0001). The most commonly used treatments were oral rehydration solution (12.0% of episodes) and antibiotics (6.0%). No bacterial or parasitic pathogens were associated with PD; but norovirus, rotavirus and sapovirus were each significantly more prevalent in PD stools compared with baseline stools, with relative risks of 12.4, 6.9 and 6.2, respectively. Fifty-nine per cent of the PD specimens tested were negative for all studied pathogens. CONCLUSIONS: PD occurs with a frequency of approximately 1 case per 5 person-years in US infants and young children. It seems to be a generally benign illness, with only 28% of cases presenting to medical care. Although viral pathogens seem to cause a minority of PD episodes in this population, most are not due to currently known infectious agents.

Animals↗
PubMed2006

Nausea and vomiting in pregnancy: maternal characteristics and risk factors.

Nausea with or without vomiting (NVP) is probably the most frequently reported medical complaint of pregnancy, but few studies have considered risk factors for its development. We used data from an ongoing epidemiological study of pregnancies in four regional centres. Mothers of infants with congenital malformations (n = 17,158) and a sample of normal infants (n = 5,329) were interviewed within 6 months of delivery by trained nurse-interviewers using a standardised questionnaire. For all risk factors investigated, odds ratios and 95% confidence intervals were calculated using multiple logistic regression, controlling for potential confounders. The cumulative incidence (risk) of NVP was 67%. The risk of NVP and its timing during pregnancy were similar for mothers of malformed and normal infants, so data were combined. No changes in the NVP risk were observed over the 20-year study period. The risk decreased with increasing age, but increased with increasing gravidity. The risk also increased with increasing number of prior miscarriages. Further, within each gravidity category, the risk was higher for twin births than for singletons. Women who reported onset of NVP after the first trimester differed demographically from women whose NVP began earlier: they were less-well educated, had lower incomes, and were more likely to be black. The finding that the number of prior pregnancies, both complete and incomplete, and number of fetuses independently appear to increase the risk of NVP suggests a fetal 'dose' effect. Together with selected demographic characteristics that differentiate early- vs. late-onset NVP, these findings warrant further investigation.

Abortion, Spontaneous↗
PubMed2005

Recent trends in use of herbal and other natural products.

BACKGROUND: The benefits of herbal and other natural products (dietary supplements) are increasingly cited in the media. Dramatic increases in use reported during the last decade have led to growing concerns about efficacy and safety. METHODS: To determine which dietary supplements American adults use, whether the prevalence has continued to increase in recent years, and whether popularity of individual supplements has changed, demographic information and details of use of all medicines and dietary supplements in the preceding week were obtained by telephone interview from February 1998 through December 2002 from households in 48 contiguous states and the District of Columbia. Participants included randomly selected residents of households with telephones; compared with 2000 US Census data, participants were representative of the US population. The main outcome measure was the weekly prevalence of dietary supplement use, alone or in a multicomponent product. RESULTS: There were 8470 subjects 18 years or older. The annual prevalence of dietary supplement use increased from 14.2% in 1998-1999 to 18.8% in 2002. Although use did not change among younger subjects, it doubled for men and women 65 years or older. Use of Ginkgo biloba and Panax ginseng declined during the study, while lutein use increased dramatically, because of its addition to multivitamin products. The overall 2002 prevalence excluding lutein use was 13.9%. CONCLUSIONS: The popularity of specific supplements has varied over time and differs according to age and sex. The sharp increase in supplement use in the 1990s appears to have slowed. However, the addition of supplements, such as lutein and lycopene, to mainstream multivitamins has become an important source of exposure.

Adult↗
PubMed2005

Gulf War veterans and hemifacial microsomia.

BACKGROUND: Concerns have been raised that more infants with Goldenhar syndrome were born to U.S. Gulf War veterans than expected. Goldenhar syndrome is considered a variant of the malformation hemifacial microsomia (HFM). We used data collected from a case-control study of HFM to estimate risk in relation to parental military service and, in particular, Gulf War service. METHODS: Cases with HFM who were three years old or younger were identified at craniofacial clinics in 24 U.S. cities and matched to controls by age and pediatrician. The mothers of 232 cases and 832 controls were interviewed between April 1996 and November 2002 about pregnancy events and exposures, including military service before the child was born and Gulf War deployment five to 11 years before the child was born. Odds ratios were adjusted for family income, race, and body mass index in early pregnancy. RESULTS: Four (1.7%) case mothers and 10 (1.2%) control mothers served in the military. Among fathers, 30 (12.9%) cases and 100 (12.0%) controls served in the military. The parents of four (1.7%) cases and 23 (2.8%) controls served in the Gulf War (multivariate adjusted odds ratio [MVOR], 0.8; 95% confidence interval [CI], 0.3-2.3). All four case parents with Gulf War service were in the Army compared to 9 of 23 control parents. The MVOR for parental Gulf War service in the Army was 2.8 (95% CI, 0.8-9.6). The corresponding MVOR for any parental service in the Army was 2.4 (95% CI, 1.4-4.2), based on 22 cases and 45 controls. CONCLUSIONS: The risk of HFM in offspring was not associated with parental service in the Gulf War five to 11 years before birth. The odds ratio for service in the Army was independent of Gulf War service and was associated with a modest increase in risk. Our findings for service in the Army may be confounded by unmeasured lifestyle factors.

Case-Control Studies↗
PubMed2005

Post-marketing surveillance using pharmacy-based cohorts: results of a pilot study.

PURPOSE: To assess the feasibility of recruiting subjects for follow-up studies of drug exposures using pharmacy records but without involving dispensing pharmacists. METHODS: Working with Eckerd Corporation, a large chain pharmacy, we attempted to enroll subjects taking either hyoscyamine (Levsin and others) or dicyclomine (Bentyl and others). Adults who filled prescriptions during the recruitment period were randomly assigned to one of four enrollment approaches that used a script and materials we provided: (1) an introductory phone call from an Eckerd pharmacy technician with an offer of a $5 payment; (2) an introductory phone call with no payment; (3) a questionnaire mailed from Eckerd with introductory letters enclosed and an offer of a $5 payment and (4) the same mailed packet but with no payment offered. Willing subjects responded directly to us; they received a follow-up questionnaire approximately 6 weeks following enrollment. This method also provided limited information about subjects who chose not to enroll, permitting us to assess the representativeness of the study population. RESULTS: The enrollment rates for the four groups were 35, 22, 21 and 17% respectively. Rates of completion of the follow-up questionnaire were 86, 83, 83 and 79% respectively. Participants appeared to be representative of the target population. The differential cost per enrolled subject in each group was $39.25, $50.45, $41.95 and $48.26 respectively. CONCLUSIONS: This method provides an efficient way to create cohorts of users of specific prescription medications, with enrollment and retention rates that compare favorably with other approaches, allows a limited evaluation of representativeness, and is logistically feasible.

Adolescent↗
PubMed2005

Use of postmenopausal hormone therapy since the Women's Health Initiative findings.

PURPOSE: To assess how use of postmenopausal hormone therapy (PHT) has changed since the Women's Health Initiative (WHI) trial was halted early due to an excess risk of stroke and other adverse outcomes. To estimate whether use of alternative drugs to treat menopausal symptoms (e.g., selective serotonin reuptake inhibitors [SSRIs], soy) has increased. METHODS: Women were interviewed in the Slone Survey, a random-digit-dial (RDD) survey of current medication use in a representative national sample. Information was obtained on PHT including dose, route, and reason for use, and on use of alternative drugs to treat menopausal symptoms. There were 3853 women aged >or=50 years, interviewed from 1/2001 to 6/2004. RESULTS: The average weekly prevalence of PHT declined 57%, from 28% in the first half of 2002 to 12% in the first half of 2004. Use declined for conjugated estrogens (CE) and for other estrogens, taken either alone or with progestin. The decrease exceeded 50% in most strata of age, race, education, and region. The proportion of PHT users taking 0.3 mg CE did not change. Comparing prevalence in 2004 with prevalence in 2002, there was no material increase in use of black cohosh (2.0% in 2004) or soy (2.0%) and use of SSRIs was somewhat lower (8.9%). CONCLUSIONS: These population-based usage data demonstrate a large decline in PHT use among women of postmenopausal age. The proportion of CE users taking lower doses has not increased. On a population basis, millions fewer women are using PHT in 2004 than before the WHI results were published, but there has been no appreciable increase in use of alternative therapies for menopausal symptoms over the same period.

Complementary Therapies↗
PubMed2005

Trends and predictors of folic acid awareness and periconceptional use in pregnant women.

OBJECTIVE: The purpose of this study was to describe recent trends in folic acid awareness and use in the periconceptional period among pregnant women in relation to maternal sociodemographic and other relevant factors. STUDY DESIGN: From 1988 to 2002, 16,555 women from the Slone Epidemiology Center Birth Defects Study were interviewed about medication use before and during pregnancy (which included multivitamins and folic acid), about whether they were aware of any vitamins that might decrease the risk of birth defects, and about sociodemographic and medical factors. RESULTS: Awareness of folic acid benefits increased from 0 in 1988 to 50% in 1996 and thereafter. The use of folic acid in the periconceptional period increased from 15% in 1988 to 40% in the last few years. Maternal education was a strong independent predictor of both awareness and use as were ethnicity, whether the pregnancy was wanted, family income, and whether a health care provider was consulted before planning. CONCLUSION: Promoting the use of folic acid supplements, particularly among these disadvantaged groups, is essential to further decrease the prevalence of neural tube defects.

Adult↗
PubMed2005

Use of over-the-counter medications during pregnancy.

OBJECTIVE: The most common medications used in pregnancy are nonprescription or over-the-counter medications, although there has been little research on their risks or safety. We describe the patterns of over-the-counter medication use among pregnant women. STUDY DESIGN: Data were collected in 2 case-control studies of birth defects: the Slone Epidemiology Center Birth Defects Study (BDS) and the National Birth Defects Prevention Study (NBDPS). RESULTS: Among 7563 mothers of malformed and nonmalformed offspring in the Slone Epidemiology Center Birth Defects Study and 2970 mothers of nonmalformed offspring in the National Birth Defects Prevention Study, acetaminophen, ibuprofen, and pseudoephedrine were used by at least 65%, 18%, and 15%, respectively. Among women in the Slone Epidemiology Center Birth Defects Study, the use in pregnancy of aspirin and chlorpheniramine decreased from 1976 to 2004 and of ibuprofen, pseudoephedrine, diphenhydramine, dextromethorphan, and guaifenesin increased. Among women in the National Birth Defects Prevention Study, the use of acetaminophen, pseudoephedrine, diphenhydramine, and guaifenesin was higher during pregnancy than before pregnancy. CONCLUSION: Findings show that over-the-counter medications are used by most pregnant women. Studies that examine specific over-the-counter medications in relation to specific birth defects are necessary to better inform pregnant women about risks and safety.

Acetaminophen↗
PubMed2005

Methylenetetrahydrofolate reductase polymorphisms and the risk of gestational hypertension.

BACKGROUND: Evidence on the association of 5,10 methylentetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms in women with gestational hypertension is inconsistent. It is also unknown whether the fetal genotype is relevant, or whether folic acid supplementation modifies this association. METHODS: The study population was composed of U.S. and Canadian white women with nonmalformed infants participating in the Slone Epidemiology Center Birth Defects Study between 1993 and 2000. Women were interviewed within 6 months after delivery regarding multivitamin use in pregnancy and the occurrence of gestational hypertension, among other factors. DNA was extracted from cheek swabs and gene alleles determined by restriction fragment length polymorphism analysis. We compared the prevalence of the 677TT/CT and 1298CC/AC genotypes between cases with gestational hypertension (54 mothers and their 51 offspring) and controls (100 mothers and their 99 offspring). We also estimated odds ratios (ORs) and 95% confidence intervals (CIs) using conditional logistic regression to control for geographic region and calendar year. RESULTS: The T allele was present in 69% of women with gestational hypertension versus 57% of control women (compared with 677CC, OR = 1.9; 95% CI = 0.9-4.0). The offspring of case and control women had a 677TT/CT genotype prevalence of 68% and 47%, respectively (2.4; 1.1-5.0). Among women supplemented with folic acid during the first 5 months of pregnancy, the ORs for maternal and fetal 677TT/CT genotypes were 0.9 (0.3-2.5) and 2.1 (0.7-6.0), respectively. Neither maternal nor fetal 1298CC/AC genotypes were associated with an increased risk of gestational hypertension. CONCLUSION: Maternal and fetal MTHFR C677T polymorphism may be associated with a moderately increased risk of gestational hypertension, and there is a suggestion that this association may be diminished among women receiving folate supplementation during pregnancy.

Adult↗