T L Burns

University of Iowa, Iowa City, Iowa, United States

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Publications (130)550.76 Total impact

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    ABSTRACT: Background: Adverse associations between maternal pesticide exposure and neural tube defects (NTDs) have been suggested but not consistently observed. This study used data from the multisite National Birth Defects Prevention Study to examine associations between maternal periconceptional (1 month preconception through 2 months postconception) occupational pesticide exposure and NTDs. Methods: Mothers of 502 NTD cases and 2950 unaffected live-born control infants with estimated delivery dates from 1997 through 2002 were included. Duration, categorical intensity scores, and categorical frequency scores for pesticide classes (e.g., insecticides) were assigned using a modified, literature-based job-exposure matrix and maternal-reported occupational histories. Adjusted odds ratios (aORs) and 95% confidence intervals were estimated based on fitted multivariable logistic regression models that described associations between maternal periconceptional occupational pesticide exposure and NTDs. The aORs were estimated for pesticide exposure (any [yes/no] and cumulative exposure [intensity × frequency × duration] to any pesticide class, each pesticide class, or combination of pesticide classes) and all NTD cases combined and NTD subtypes. Results: Positive, but marginally significant or nonsignificant, aORs were observed for exposure to insecticides + herbicides for all NTD cases combined and for spina bifida alone. Similarly, positive aORs were observed for any exposure and cumulative exposure to insecticides + herbicides + fungicides and anencephaly alone and encephalocele alone. All other aORs were near unity. Conclusion: Pesticide exposure associations varied by NTD subtype and pesticide class. Several aORs were increased, but not significantly. Future work should continue to examine associations between pesticide classes and NTD subtypes using a detailed occupational pesticide exposure assessment and examine pesticide exposures outside the workplace. Birth Defects Research (Part A), 2014. © 2014 Wiley Periodicals, Inc.
    Birth Defects Research Part A Clinical and Molecular Teratology 08/2014; · 2.27 Impact Factor
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    ABSTRACT: Physical activity improves bone strength and reduces the risk for osteoporotic fractures. However, there are substantial gaps in our knowledge as to when, how and how much activity is optimal for bone health.
    British journal of sports medicine. 05/2014;
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    ABSTRACT: Depression has been associated with reduced bone mass in adults, but the mechanisms remain unclear. In addition, little is known about the association between depression and bone health during growth and development. To address this knowledge gap, we examined bone density and structure in 222 adolescents and young adults (69% females, mean ± SD age: 19.0 ± 1.5 years), enrolled within one month of starting a selective serotonin reuptake inhibitor (SSRI) or unmedicated. Psychiatric functioning was assessed with self-report and researcher-administered instruments, including the Longitudinal Interval Follow-up Evaluation for Adolescents (A-LIFE). Anthropometric and laboratory measures included dual-energy x-ray absorptiometry and peripheral quantitative computed tomography scans. Linear multivariable regression analysis tested the association between depression and bone mass, after accounting for relevant confounders. The presence of current depression was associated with a significant reduction in age-sex-height-race-specific bone mineral density (BMD) and content (BMC) of total body less head and lumbar spine. The findings varied by assessment method with self-report scales, capturing symptom severity over the prior week or two, yielding the weakest associations. Depression was also associated with reduced cortical thickness and a trend for increased endosteal circumference. In contrast, generalized anxiety disorder was not associated with bone deficits. In sum, depressive illness is associated with significantly lower bone mass in youths. Future investigations must examine whether bone recovery is possible following depression remission or whether remedial interventions are warranted to optimize bone mass in order to minimize the long-term risk of osteoporosis. © 2014 American Society for Bone and Mineral Research
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 04/2014; · 6.04 Impact Factor
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    ABSTRACT: Abstract Objective: Second-generation antipsychotics (SGAs) cause weight gain and cardiometabolic abnormalities in children and adolescents. Less well-investigated is the outcome of these adverse events following SGA discontinuation, which we examined. Methods: Medically healthy 7 to 17-year-old patients treated with risperidone for ≥6 months were enrolled and returned for follow-up, 1.5 years later. Treatment history was extracted from the medical and pharmacy records. Anthropometric and laboratory measurements were obtained at each research visit. Multivariable linear regression analysis and Fisher's exact test were used to compare participants who remained on risperidone at follow-up (Risp Cont Group) with those who had discontinued SGA treatment (SGA Disc Group) and those who had switched to another SGA (SGA Cont Group). Correlational analyses examined the association between change in age-sex specific body mass index (BMI) z score between study entry and follow-up and change in cardiometabolic outcomes. Results: The sample consisted of 101 participants (93% male) with a mean age of 11.7±2.6 years at study entry. The majority had an externalizing disorder and received 0.03±0.02 mg/kg/day of risperidone, for 2.5±1.6 years. At follow-up, 18% (n=18) were in the SGA Disc Group and 9% (n=9) were in the SGA Cont Group. BMI z score decreased in the SGA Disc Group, remained unchanged in the Risp Cont Group (n=74), and increased in the SGA Cont Group. Importantly, the change in BMI z score between study entry and follow-up was significantly correlated with the change in systolic and diastolic blood pressure z scores, heart rate, waist circumference, percent body fat, inflammatory markers, fasting total insulin, homeostatic model assessment insulin resistance index (HOMA-IR), C-peptide, total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol, triglycerides, triglycerides/HDL ratio, and leptin. Conclusions: Following several years of treatment, risperidone discontinuation is associated with a reversal of the excessive weight gain, mediated by a negative energy balance, and a corresponding improvement in cardiometabolic parameters.
    Journal of child and adolescent psychopharmacology 04/2014; 24(3):120-9. · 2.59 Impact Factor
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    ABSTRACT: Adult bone diseases, especially osteoporosis, lead to increased risk of fracture which in turn is associated with substantial morbidity, mortality, and financial costs. Clinically, osteoporosis is defined by low bone mineral density (BMD); however, increasing evidence suggests that the micro-architectural quality of trabecular bone (TB) is an important determinant of bone strength and fracture risk. Accurate measures of TB thickness and marrow spacing is of significant interest for early diagnosis of osteoporosis or treatment effects. Here, we present a new robust algorithm for computing TB thickness and marrow spacing at a low resolution achievable in vivo. The method uses a star-line tracing technique that effectively deals with partial voluming effects of in vivo imaging with voxel size comparable to TB thickness. Also, the method avoids the problem of digitization associated with conventional algorithms based on sampling distance transform along skeletons. Accuracy of the method was examined using computer-generated phantom images while the robustness of the method was evaluated on human ankle specimens in terms of stability across a wide range of voxel sizes, repeat scan reproducibility under in vivo conditions, and correlation between thickness values computed at ex vivo and in vivo imaging resolutions. Also, the sensitivity of the method was examined by evaluating its ability to predict the bone strength of cadaveric specimens. Finally, the method was evaluated in a human study involving 40 healthy young-adult volunteers (age: 19 to 21 years; 20 males and 20 females) and ten athletes (age: 19 to 21 years; 6 males and 4 females). Across a wide range of voxel sizes, the new method is significantly more accurate and robust as compared to conventional methods. Both TB thickness and marrow spacing measures computed using the new method demonstrated strong associations (R2 2 [0:83; 0:87]) with bone strength. Also, the TB thickness and marrow spacing measures allowed discrimination between male and female volunteers (p 2 [0:01; 0:04]) as well as between athletes and non-athletes (p 2 [0:005; 0:03]).
    IEEE transactions on bio-medical engineering 03/2014; · 2.15 Impact Factor
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    ABSTRACT: Controversy persists concerning the impact of community water fluoridation on bone health in adults, and few studies have assessed relationships with bone at younger ages. Ecological studies of fluoride's effects showed some increase in bone mineral density of adolescents and young adults in areas with fluoridated water compared with non-fluoridated areas. However, none had individual fluoride exposure measures. To avoid ecological fallacy and reduce bias, we assessed associations of average daily fluoride intake from birth to age 15 yr for Iowa Bone Development Study cohort members with age 15 yr dual-energy x-ray absorptiometry (DXA) bone outcomes (whole body, lumbar spine, and hip), controlling for known determinants (including daily calcium intake, average daily time spent in moderate-to-vigorous intensity physical activity, and physical maturity). Mean (SD) daily fluoride intake was 0.66 mg (0.24) for females and 0.78 mg (0.30) for males. We found no significant relationships between daily fluoride intake and adolescents' bone measures in adjusted models (for 183 females, all p values ≥ .10 and all partial R(2) ≤ 0.02; for 175 males, all p values ≥ .34 and all partial R(2) ≤ 0.01). The findings suggest that fluoride exposures at the typical levels for most US adolescents in fluoridated areas do not have significant effects on bone mineral measures.
    Journal of dental research 01/2014; · 3.46 Impact Factor
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    ABSTRACT: Choanal atresia causes serious posterior nasal obstruction. This defect is the leading cause of nasal surgery in newborns, although its etiology is largely unknown. Data from the National Birth Defects Prevention Study, a population-based case-control study, were used to examine associations between maternal self-reports of exposures and occurrence of choanal atresia in their offspring. Overall, 117 case and 8350 control mothers with deliveries from 1997-2007 provided telephone interview reports of pre-pregnancy (one year before conception) and periconceptional (one month before through three months after conception) exposures. Exposures analyzed were pre-pregnancy dietary intake, pre-pregnancy and periconceptional caffeine consumption, and periconceptional cigarette smoking, alcohol drinking, and medication use. Independent associations between each exposure and all choanal atresia cases combined (n=117) and isolated choanal atresia cases (those without additional unrelated major defects; n=61) were examined. Odds ratios (ORs), both unadjusted (uORs) and adjusted (aORs) for potential confounders, and 95% confidence intervals (CI)s were estimated using unconditional logistic regression analysis. For all choanal atresia cases combined, positive associations were observed with maternal pre-pregnancy intake in the highest quartile for vitamin B-12 (aOR=1.9; CI=1.1,3.1), zinc (aOR=1.7; CI=1.0,3.1), and niacin (aOR=1.8; CI=1.0,3.1), and intake in the lowest quartile for methionine (aOR=1.6; CI=1.0,2.6) and vitamin D (aOR=1.6; CI=1.0,2.4) compared to intake in the two intermediate quartiles combined. Further, a positive association was observed with periconceptional use of thyroid medications (uOR=2.6; CI=1.0,6.3) compared to no use of such medications. Among isolated choanal atresia cases, negative associations were observed for pantothenic acid (aOR=0.4; CI=0.2,0.9) and fat (aOR=0.5; 95% CI=0.2,1.0) intake in the lowest quartile compared to that in the intermediate quartiles, and positive associations were observed for periconceptional cigarette smoking (aOR=2.3; CI=1.1,4.7) compared to no smoking and pre-pregnancy daily coffee intake of 3 or more cups (aOR=2.5; CI=1.1,5.6) compared to intake of less than 1 cup per day. The positive association for periconceptional exposure to thyroid medications also persisted for isolated choanal atresia cases (uOR=4.0; CI=1.1,11.2). Because of the large number of associations tested, these findings may be due to chance. Alternatively, they may contribute new hypotheses regarding the etiology of choanal atresia; thus, requiring replication in additional studies.
    European journal of medical genetics 01/2014; · 1.57 Impact Factor
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    ABSTRACT: This study examined the association between physical activity (PA) and bone mineral content (BMC; gram) from middle childhood to middle adolescence and compared the impact of vigorous-intensity PA (VPA) over moderate- to vigorous-intensity PA (MVPA). Participants from the Iowa bone development study were examined at ages 5, 8, 11, 13, and 15 years (n = 369, 449, 452, 410, and 307, respectively). MVPA and VPA (minutes per day) were measured using ActiGraph accelerometers. Anthropometry was used to measure body size and somatic maturity. Spine BMC and hip BMC were measured via dual-energy x-ray absorptiometry. Sex-specific multi-level linear models were fit for spine BMC and hip BMC, adjusted for weight (kilogram), height (centimeter), linear age (year), non-linear age (year(2)), and maturity (pre peak height velocity vs. at/post peak height velocity). The interaction effects of PA × maturity and PA × age were tested. We also examined differences in spine BMC and hip BMC between the least (10th percentile) and most (90th percentile) active participants at each examination period. Results indicated that PA added to prediction of BMC throughout the 10-year follow-up, except MVPA, did not predict spine BMC in females. Maturity and age neither modify the PA effect for males nor females. At age 5, the males at the 90th percentile for VPA had 8.5% more hip BMC than males in the 10th percentile for VPA. At age 15, this difference was 2.0%. Females at age 5 in the 90th percentile for VPA had 6.1% more hip BMC than those in the 10th percentile for VPA. The age 15 difference was 1.8%. VPA was associated with BMC at weight-bearing skeletal sites from childhood to adolescence, and the effect was not modified by maturity or age. Our findings indicate the importance of early and sustained interventions that focus on VPA. Approaches focused on MVPA may be inadequate for optimal bone health, particularly for females.
    Frontiers in Endocrinology 01/2014; 5:112.
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    ABSTRACT: Purpose: To compare the reproducibility of SD-OCT-based ganglion-cell-layer-plus-inner-plexiform-layer (GCL+IPL) thickness measurements for glaucoma patients obtained using both a publicly available and a commercially available algorithm. Methods: Macula SD-OCT volumes (Cirrus, Carl Zeiss Meditec, Inc., Dublin, CA, 200 x 200 x 1024 voxels, 6 x 6 x 2 mm(3)) were obtained prospectively in both eyes of patients with open-angle glaucoma or glaucoma suspicion on two separate visits within four months. The combined GCL+IPL thickness was computed for each SD-OCT volume within an elliptical annulus centered at the fovea based on two algorithms: (1) a previously published graph-theoretic layer segmentation approach developed at The University of Iowa and (2) the Ganglion Cell Analysis module of version 6 of the Zeiss Cirrus software. The mean overall thickness in the elliptical annulus was computed as well as the thickness within six sectors. For statistical analyses, eyes with an SD-OCT volume with a low signal strength (< 6), image acquisition errors, or errors in performing the commercial GCL+IPL analysis in at least one of the repeat acquisitions were excluded. Results: Using 104 eyes (from 56 patients) with repeated measurements, the intraclass correlation coefficient for the overall elliptical annular GCL+IPL thickness was 0.98 (95% CI: 0.97-0.99) using the Iowa algorithm and 0.95 (95% CI: 0.93-0.97) using the Cirrus algorithm; the intervisit standard deviation was 1.55 µm (Iowa) and 2.45 µm (Cirrus); and the coefficient of variation was 2.2% (Iowa) and 3.5% (Cirrus), p < 0.0001. Conclusions: SD-OCT-based GCL+IPL thickness measurements in early glaucoma patients are highly reproducible.
    Investigative ophthalmology & visual science 09/2013; · 3.43 Impact Factor
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    ABSTRACT: Objective: To examine associations among age, physical activity (PA), and birth cohort on body mass index (BMI) percentiles in men. Design and Methods: Longitudinal analyses using quantile regression were conducted among men with ≥ two examinations between 1970 and 2006 from the Aerobics Center Longitudinal Study (n=17,759). Height and weight were measured; men reported their PA and were categorized as inactive, moderately or highly active at each visit. Analyses allowed for longitudinal changes in PA. Results: BMI was greater in older than younger men and in those born in 1960 than those born in 1940. Inactive men gained weight significantly more rapidly than active men. At the 10(th) percentile, increases in BMI among inactive, moderately active, and highly active men were 0.092, 0.078, and 0.069 kg/m(2) per year of age, respectively. The 10(th) percentile increased by 0.081 kg/m(2) per birth year and by 0.180 kg/m(2) at the 90(th) percentile, controlling for age. Conclusion: Although BMI increased with age, PA reduced the magnitude of the gradient among active compared to inactive men. Regular PA had an important, protective effect against weight gain. This study provides evidence of the utility of quantile regression to examine the specific causes of the obesity epidemic.
    Obesity 09/2013; · 3.92 Impact Factor
  • Sonali S Patel, Trudy L Burns
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    ABSTRACT: Advances have been made in identifying genetic etiologies of congenital heart defects. Through this knowledge, preventive strategies have been designed and instituted, and prospective parents are counseled regarding their risk of having an affected child. Great strides have been made in genetic variant identification, and genetic susceptibility to environmental exposures has been hypothesized as an etiology for congenital heart defects. Unfortunately, similar advances in understanding have not been made regarding strategies to prevent nongenetic risk factors. Less information is available regarding the potential adverse effect of modifiable risk factors on the fetal heart. This review summarizes the available literature on these modifiable exposures that may alter the risk for congenital heart disease. Information regarding paternal characteristics and conditions, maternal therapeutic drug exposures, parental nontherapeutic drug exposures, and parental environmental exposures are presented. Factors are presented in terms of risk for congenital heart defects as a group. These factors also are broken down by specific defect type. Although additional investigations are needed in this area, many of the discussed risk factors present an opportunity for prevention of potential disease.
    Pediatric Cardiology 08/2013; · 1.20 Impact Factor
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    ABSTRACT: BACKGROUND: Elevated blood pressure (BP) levels in childhood have been associated with subsequent atherosclerosis. However, it is uncertain whether this risk is attenuated in individuals who acquire normal BP by adulthood. The present study examined the effect of child and adult BP levels on carotid artery intima-media thickness (cIMT) in adulthood. METHODS AND RESULTS: The cohort consisted of 4,210 participants from four prospective studies (mean follow-up 23 years). Childhood elevated BP was defined according to the tables from the National High Blood Pressure Education Program. In adulthood BP was classified as elevated for individuals with systolic BP ≥120mmHg, diastolic BP ≥80mmHg or with self-reported use of antihypertensive medications. cIMT was measured in the left common carotid artery. High IMT was defined as an IMT ≥age-, sex-, race-, and cohort-specific 90th percentile. Individuals with persistently elevated BP and individuals with normal childhood BP, but elevated adult BP had increased risk of high cIMT (RR[95%CI]) 1.82[1.47-2.38] and 1.57[1.22-2.02], respectively) when compared to individuals with normal child and adult BP. In contrast, individuals with elevated BP as children but not as adults did not have significantly increased risk (1.24[0.92-1.67]). In addition, these individuals had lower risk of increased cIMT (0.66[0.50-0.88]) when compared to those with persistently elevated BP. The results were consistent when controlling for age, sex, adiposity and when different BP definitions were applied. CONCLUSIONS: Individuals with persistently elevated BP from childhood to adulthood had increased risk of carotid atherosclerosis. This risk was reduced if elevated BP during childhood resolved by adulthood.
    Circulation 06/2013; · 15.20 Impact Factor
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    ABSTRACT: BACKGROUND: Neural tube defects (NTD)s, which occur when the neural tube fails to close during early gestation, are some of the most common birth defects worldwide. Alcohol is a known teratogen and has been shown to induce NTDs in animal studies, although most human studies have failed to corroborate these results. Using data from the National Birth Defects Prevention Study, associations between maternal reports of periconceptional (1 month prior through 2 months postconception) alcohol consumption and NTDs were examined. METHODS: NTD cases and unaffected live born control infants, delivered from 1997 through 2005, were included. Interview reports of alcohol consumption (quantity, frequency, variability, and type) were obtained from 1223 case mothers and 6807 control mothers. Adjusted odds ratios (aOR)s and 95% confidence intervals were estimated using multivariable logistic regression analysis. RESULTS: For all NTDs combined, most aORs for any alcohol consumption, one or more binge episodes, and different type(s) of alcohol consumed were near unity or modestly reduced (≥0.7<aOR≤1.1) and were not statistically significant. Findings were similar for individual NTD subtypes. CONCLUSIONS: These findings suggest no elevated association between maternal periconceptional alcohol consumption and NTDs. Underreporting of alcohol consumption, due to negative social stigma associated with alcohol consumption during pregnancy, and limited reports for mothers with early pregnancy loss of a fetus with an NTD may have affected the estimated odds ratios. Future studies should aim to increase sample sizes for less prevalent subtypes, reduce exposure misclassification, and improve ascertainment offetal deaths and elective terminations. Birth Defects Research (Part A), 2013. © 2013 Wiley Periodicals, Inc.
    Birth Defects Research Part A Clinical and Molecular Teratology 03/2013; · 2.27 Impact Factor
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    ABSTRACT: OBJECTIVE: To examine the relative importance of sedentarism and moderate-to-vigorous physical activity for adiposity development in children and adolescents. STUDY DESIGN: A total of 277 boys and 277 girls (95% white; two-thirds of parents with college graduation or higher education) from the Iowa Bone Development Cohort Study completed body fat and accelerometry measurement at examinations of 8, 11, 13, and/or 15 years of age (during 2000-2009). The main exposure was accelerometry-measured sedentary time, frequency of breaks in sedentary time, and moderate- to vigorous-intensity physical activity time. The outcome was dual energy x-ray absorptiometry-measured body fat mass. RESULTS: Adjusted for age, height, physical maturity, and sedentary time, growth models showed that high moderate-to-vigorous physical activity time was associated with low body fat mass in both boys (coefficient β = -0.10 ± 0.02) and girls (β = -0.05 ± 0.01; P < .01). However, sedentary time and frequency of breaks in sedentary time were not associated with body fat mass. CONCLUSIONS: This study does not support an independent effect of sedentarism on adiposity. The preventive effect of moderate- to vigorous-intensity physical activity on adiposity in children and adolescents remained strong after adjusting for the effect of sedentarism.
    The Journal of pediatrics 01/2013; · 4.02 Impact Factor
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    ABSTRACT: OBJECTIVE: To investigate whether the rate of weight gain is associated with cardiometabolic risk, independent of weight measured concurrently. STUDY DESIGN: Healthy 7- to 17-year-old risperidone-treated patients (N = 105, 88% were boys) had blood pressure, anthropometry, and laboratory tests performed. Growth history was extracted from medical records. The rate of change in age- and sex-adjusted weight and body mass index (BMI) z score after the initiation of risperidone was individually modeled. Multivariable linear regression analyses explored the association of the rate of weight or BMI z score change with cardiometabolic outcomes, independent of last measured weight or BMI z score, respectively. RESULTS: Following a mean of 1.9 years (SD = 1.0) of risperidone treatment, the absolute increase in weight and BMI z scores was 0.61 (SD = 0.61) and 0.62 (SD = 0.73), respectively. After controlling for the final weight z score, the rate of change in weight z score was significantly associated with final glucose (P < .04), C-peptide (P < .004), the homeostasis model assessment insulin resistance index (P < .02), high-density lipoprotein (HDL) cholesterol (P < .0001), a metabolic syndrome score (P < .005), adiponectin (P < .04), and high-sensitivity C-reactive protein (P < .04). After controlling for the final BMI z score, the rate of change in BMI z score was associated with final HDL cholesterol (P < .04), leptin (P < .03), and adiponectin (P < .04), with a suggestion of an association with the final homeostasis model assessment insulin resistance index (P < .08). CONCLUSIONS: Compared with weight measured concurrently, the rate of weight gain in risperidone-treated children accounts for an equal or larger share of the variance in certain cardiometabolic outcomes (eg, HDL cholesterol [ΔR(2) = 8% vs ΔR(2) = 11%] and high-sensitivity C-reactive protein [ΔR(2) = 5% vs ΔR(2) = 9%]) and may serve as a treatment target.
    The Journal of pediatrics 12/2012; 161:1010-1015. · 4.02 Impact Factor
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    ABSTRACT: BACKGROUND: Animal studies have shown that high doses of caffeine might cause congenital limb deficiencies (LDs); however, no epidemiologic studies have explored this relation. METHODS: This case-control study assessed associations between maternal dietary caffeine and congenital LDs using data from the National Birth Defects Prevention Study (NBDPS), with 844 LD cases and 8069 controls from 1997 to 2007. Caffeine intakes from beverages (coffee, tea, and soda) and chocolate combined and by beverage type were examined. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated for subtypes of isolated LDs (no additional major anomalies) and LDs with other major anomalies separately, comparing the odds of 10 to <100, 100 to <200, 200 to <300, and 300+ mg/day total caffeine intake to 0 to <10 mg/day. RESULTS: All total dietary caffeine intake categories of 10 mg/day and above were marginally associated with odds of all isolated LDs combined (aOR, 1.4-1.7), isolated longitudinal LDs (aOR, 1.2-1.6), and isolated transverse LDs (aOR, 1.3-1.8) compared to the lowest intake category. A dose-response pattern for total dietary caffeine intake was not observed. CONCLUSIONS: A weak increased risk of congenital LDs associated with maternal dietary caffeine consumption was observed in this study; however, risk did not vary by amount of caffeine consumed. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.
    Birth Defects Research Part A Clinical and Molecular Teratology 08/2012; · 2.27 Impact Factor
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    ABSTRACT: Although the descriptive epidemiology of atrioventricular septal defects (AVSDs), a group of serious congenital heart defects (CHDs), has been recently reported, non-genetic risk factors have not been consistently identified. Using data (1997-2005) from the National Birth Defects Prevention Study, an ongoing multisite population-based case-control study, the association between selected non-genetic factors and non-syndromic AVSDs was examined. Data on periconceptional exposures to such factors were collected by telephone interview from 187 mothers of AVSD case infants and 6,703 mothers of unaffected infants. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated from logistic regression models. Mothers who reported cigarette smoking during the periconceptional period were more likely to have infants with AVSDs compared with non-smokers, independent of maternal age, periconceptional alcohol consumption, infant gestational age, family history of CHDs, and study site (aOR 1.5, 95% CI 1.1-2.4). The association was strongest in mothers who smoked more than 25 cigarettes/day. In addition, mothers with periconceptional passive smoke exposure were more likely to have infants with AVSDs than unexposed mothers, independent of maternal age, active periconceptional smoking, infant gestational age, and family history of CHDs (aOR 1.4, 95% CI 1.0-2.0). No associations were observed between AVSDs and maternal history of a urinary tract infection or pelvic inflammatory disease, maternal use of a wide variety of medications, maternal occupational exposure, parental drug use, or maternal alcohol consumption. If the results of this preliminary study can be replicated, minimizing maternal active and passive smoke exposure may decrease the incidence of AVSDs. © 2012 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 08/2012; 158A(10):2447-2455. · 2.30 Impact Factor
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    ABSTRACT: Atrioventricular septal defects (AVSDs) account for 7% of all congenital cardiovascular malformations. The atrioventricular septum (AVS) is the portion of the septal tissue that separates the right atrium from the left ventricle; deficiency of the AVS contributes to the AVSD phenotype. A study of case and control families was performed to identify whether an intermediate phenotype consisting of a shortened AVS existed in relatives of children with AVSDs. AVS length (AVSL) was measured on the echocardiograms of clinically unaffected parents and siblings from families that were identified through children with nonsyndromic AVSDs and in families with no histories of congenital heart disease. No significant differences were seen between case and control family members in terms of gender, age, weight, and height. AVSLs were significantly shorter in case parents compared with control parents. Similar findings were noted within the sibling groups. There was significant evidence for two-component distributions in the case parent, case sibling, and control sibling groups after standardizing AVSL for age and body surface area. Heritability of AVSL standardized for age and body surface area was 0.82 and 0.71 in nonsyndromic case and control families, respectively. Evidence for two-component distributions from the analysis of AVSL standardized for age and body surface area for case parents and case siblings suggests the presence of an intermediate phenotype for nonsyndromic AVSD. The high heritability in the control families suggests that there may be polygenic involvement in the determination of AVSL. Broadening the definition of AVSD to include those with shortened AVSL may increase the power of genetic association and mapping studies to identify susceptibility genes for AVSD.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 04/2012; 25(7):782-9. · 2.98 Impact Factor
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    ABSTRACT: This is a consortium of large children's cohorts that contain measurements of major cardiovascular disease (CVD) risk factors in childhood and had the ability to follow those cohorts into adulthood. The purpose of this consortium is to enable the pooling of data to increase power, most importantly for the follow-up of CVD events in adulthood. Within the consortium, we hope to be able to obtain data on the independent effects of childhood and early adult levels of CVD risk factors on subsequent CVD occurrence.
    International Journal of Epidemiology 03/2012; · 6.98 Impact Factor
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    ABSTRACT: The frequency of interruptions in sedentary time (sedentary breaks) is an aspect of sedentary behaviors that may be associated with metabolic health outcomes. The aim of this study was to describe the change in the frequency of sedentary breaks during a 10-yr period from ages 5 to 15 yr. The longitudinal Iowa Bone Development Study has collected accelerometry data at approximately 5, 8, 11, 13, and 15 yr. Data from participants who wore an accelerometer at least 10 h·d(-1) and 3 d per data collection episode were used (423 children at age 5 yr, 550 children at age 8 yr, 520 children at age 11 yr, 454 children at age 13 yr, and 344 children at age 15 yr). The frequency of sedentary breaks was determined based on accelerometry data and compared by weekday/weekend, period during the day, gender, and data collection episode. The frequency of sedentary breaks decreased by >200 times per day during a 10-yr period from ages 5 to 15 yr. Linear regression models estimated a 1.84-times-per-hour decrease per year for boys and a 2.04-times-per-hour decrease per year for girls (P values < 0.0001). Both boys and girls showed significantly fewer breaks on weekdays from morning to 3:00 p.m. than on weekends from morning to 3:00 p.m. (P values < 0.0001). The frequency of sedentary breaks was slightly higher among boys than among girls (gender difference ≤ 2 times per hour; P values < 0.01 at ages 11, 13, and 15 yr). Breaks in sedentary time notably decrease during childhood and adolescence. During school hours, boys and girls have fewer breaks in sedentary time than during any other period of weekday or weekend day.
    Medicine and science in sports and exercise 12/2011; 44(6):1075-80. · 4.48 Impact Factor

Publication Stats

3k Citations
550.76 Total Impact Points

Institutions

  • 1988–2014
    • University of Iowa
      • • Department of Epidemiology
      • • Department of Pediatrics
      • • Department of Preventive and Community Dentistry
      • • Department of Internal Medicine
      Iowa City, Iowa, United States
  • 2012
    • AstraZeneca
      Tukholma, Stockholm, Sweden
  • 2011
    • University of Chicago
      • Department of Health Studies
      Chicago, IL, United States
  • 2009–2010
    • University of California, Davis
      • Department of Public Health Sciences
      Davis, CA, United States
  • 2007
    • Children's Hospital & Research Center Oakland
      Oakland, California, United States
  • 1998
    • Utah State University
      • Department of Nutrition, Dietetics and Food Sciences
      Logan, Ohio, United States
  • 1992
    • Iowa City Ambulatory Surgical Center
      Iowa City, Iowa, United States
  • 1983–1992
    • University of Michigan
      • • Department of Epidemiology
      • • Department of Psychology
      Ann Arbor, MI, United States
  • 1989
    • Mayo Clinic - Rochester
      Rochester, Minnesota, United States