Uyen-Sa D. T. Nguyen

Teratogenicity of High Vitamin A Intake

Background Studies in animals indicate that natural forms of vitamin A are teratogenic. Synthetic retinoids chemically similar to vitamin A cause birth defects in humans; as in animals, the defects appear to affect tissues derived from the cranial neural crest. Methods Between October 1984 and June 1987, we identified 22,748 pregnant women when they underwent screening either by measurement of maternal serum alpha-fetoprotein or by amniocentesis. Nurse interviewers obtained information on the womens diet, medications, and illnesses during the first trimester of pregnancy, as well as information on their family and medical history and exposure to environmental agents. We obtained information on the outcomes of pregnancy from the obstetricians who delivered the babies or from the women themselves. Of the 22,748 women, 339 had babies with birth defects; 121 of these babies had defects occurring in sites that originated in the cranial neural crest. Results For defects associated with cranial-neural-crest tis...

The impact of ethnicity, family income, and parental education on children's health and use of health services.

OBJECTIVES This study characterized ethnic disparities for children in demographics, health status, and use of services; explored whether ethnic subgroups (Puerto Rican, Cuban, and Mexican) have additional distinctive differences; and determined whether disparities are explained by differences in family income and parental education. METHODS Bivariate and multivariate analyses of data on 99,268 children from the 1989-91 National Health Interview Surveys were conducted. RESULTS Native American, Black, and Hispanic children are poorest (35%, 41% below poverty level vs 10% of Whites), least healthy (66%-74% in excellent or very good health vs 85% of Whites), and have the least well educated parents. Compared with Whites, non-White children average fewer doctor visits and are more likely to have excessive intervals between visits. Hispanic subgroup differences in demographics, health, and use of services equal or surpass differences among major ethnic groups. In multivariate analyses, almost all ethnic group disparities persisted after adjustment for family income, parental education, and other relevant covariates. CONCLUSIONS Major ethnic groups and subgroups of children differ strikingly in demographics, health, and use of services; subgroup differences are easily overlooked; and most disparities persist even after adjustment for family income and parental education.

Increasing Prevalence of Knee Pain and Symptomatic Knee Osteoarthritis: Survey and Cohort Data

BACKGROUND A recent surge in knee replacements is assumed to be due to aging and increased obesity of the U.S. population. OBJECTIVE To assess whether age, obesity, and change in radiographic knee osteoarthritis explain the trend in knee pain and osteoarthritis. DESIGN Cross-sectional, using data from 6 NHANES (National Health and Nutrition Examination Survey) surveys between 1971 and 2004 and from 3 examination periods in the FOA (Framingham Osteoarthritis) Study between 1983 through 2005. SETTING U.S. population. PARTICIPANTS NHANES participants (white or African American; aged 60 to 74 years) and FOA Study participants (mostly white; aged ≥70 years) were included. MEASUREMENTS NHANES participants were asked about pain in or around the knee on most days. In the FOA Study, participants were asked about knee pain and had bilateral weight-bearing anteroposterior knee radiography to define radiographic knee osteoarthritis. Radiographic evidence and self-reported pain were used to define symptomatic knee osteoarthritis. The age- and age- and body mass index (BMI)-adjusted prevalences of knee pain and osteoarthritis at later examinations were compared with that of earlier examinations by using the ratio of the prevalence estimates. RESULTS Age- and BMI-adjusted prevalence of knee pain increased by about 65% in NHANES from 1974 to 1994 among non-Hispanic white and Mexican American men and women and among African American women. In the FOA Study, the age- and BMI-adjusted prevalence of knee pain and symptomatic knee osteoarthritis approximately doubled in women and tripled in men over 20 years. No such trend was observed in the prevalence of radiographic knee osteoarthritis in FOA Study participants. After age adjustment, additional adjustment for BMI resulted in a 10% to 25% decrease in the prevalence ratios for knee pain and symptomatic knee osteoarthritis. LIMITATIONS Differences in sampling of FOA Study participants over time or birth cohort effects cannot be ruled out as possible explanations of the increased reporting of knee pain. Increases in prevalence at the last interval in the FOA Study might be due to differences in cohort membership by interval. CONCLUSION Results suggest that the prevalence of knee pain has increased substantially over 20 years, independent of age and BMI. Obesity accounted for only part of this increase. Symptomatic knee osteoarthritis increased but radiographic knee osteoarthritis did not. PRIMARY FUNDING SOURCE American College of Rheumatology Research and Education Foundation and National Institutes of Health. The FOA Study was funded by the National Heart, Lung, and Blood Institute (for the parent Framingham Heart Study), National Institute on Aging, and National Institute of Arthritis and Musculoskeletal and Skin Diseases (FOA Study), National Institutes of Health.

Indoor and outdoor falls in older adults are different: the maintenance of balance, independent living, intellect, and Zest in the Elderly of Boston Study.

OBJECTIVES: To identify risk factors for indoor and outdoor falls.

Outcomes, Safety, and Resource Utilization in a Collaborative Care Birth Center Program Compared With Traditional Physician-Based Perinatal Care

OBJECTIVE We compared outcomes, safety, and resource utilization in a collaborative management birth center model of perinatal care versus traditional physician-based care. METHODS We studied 2957 low-risk, low-income women: 1808 receiving collaborative care and 1149 receiving traditional care. RESULTS Major antepartum (adjusted risk difference [RD] = -0.5%; 95% confidence interval [CI] = -2.5, 1.5), intrapartum (adjusted RD = 0.8%; 95% CI = -2.4, 4.0), and neonatal (adjusted RD = -1.8%; 95% CI = -3.8, 0.1) complications were similar, as were neonatal intensive care unit admissions (adjusted RD = -1.3%; 95% CI = -3.8, 1.1). Collaborative care had a greater number of normal spontaneous vaginal deliveries (adjusted RD = 14.9%; 95% CI = 11.5, 18.3) and less use of epidural anesthesia (adjusted RD = -35.7%; 95% CI = -39.5, -31.8). CONCLUSIONS For low-risk women, both scenarios result in safe outcomes for mothers and babies. However, fewer operative deliveries and medical resources were used in collaborative care.

Factors associated with hallux valgus in a population-based study of older women and men: the MOBILIZE Boston Study.

OBJECTIVE To examine potential risk factors for hallux valgus in community-dwelling elders. METHOD Data from 600 MOBILIZE Boston Study participants (386 women and 214 men) were analyzed. Hallux valgus was defined as >15 degrees angular deviation of the hallux with respect to the first metatarsal bone toward the lesser toes. Associations of hallux valgus with age, body mass index (BMI), race, education, pes planus, foot pain, and in women, history of high heel shoe use, were assessed using sex-specific Poisson regression with robust variance estimation for risk ratios (RR) and 95% confidence intervals (CI). RESULTS Hallux valgus was present in 58% of women and 25% of men. Higher BMI was inversely associated with presence of hallux valgus in women (P trend=0.001), with the strongest inverse association observed in those with BMI of 30.0 or more compared to those with normal BMI (RR=0.7, 95% CI: 0.5, 0.9). Women, who usually wore high-heeled shoes during ages 20-64 years compared to those who did not, had increased likelihood of hallux valgus (RR=1.2, 95% CI: 1.0, 1.5). Among men, those with BMI between 25.0 and 29.9 had increased likelihood of hallux valgus compared to those with normal BMI (RR=1.9, 95% CI: 1.0, 3.5). Men with pes planus were more likely to have hallux valgus (RR=2.1, 95% CI: 1.3, 3.3) compared to men without pes planus. CONCLUSION In women, hallux valgus was associated with lower BMI and high heel use during ages 20-64, while in men, associations were observed with higher BMI and pes planus. Our results suggest that the etiologic mechanisms for hallux valgus may differ between men and women.

Effect of calcium supplementation on blood pressure in children.

OBJECTIVE To evaluate the effect of calcium supplementation on blood pressure in children. DESIGN Randomized, double-masked, placebo-controlled trial. SETTING AND PARTICIPANTS One hundred one fifth-grade students in one inner-city school. INTERVENTION Each child consumed 480 ml of juice beverages, containing either no calcium or 600 mg calcium (as calcium citrate malate) daily for 12 weeks. MEASUREMENTS At baseline we obtained nutrient data from three sets of 2-day food records on each subject. We measured blood pressure four times on each of three weekly sittings at baseline and at follow-up. Using multiple linear regression analysis, we compared mean blood pressure change in the intervention group with that in the placebo group. RESULTS There were 50 girls and 51 boys; 61 subjects were black. At baseline, mean age was 11.0 years, systolic and diastolic blood pressures were 101.7 and 57.7 mm Hg, daily total energy intake was 1966 kcal, and calcium intake was 827 mg. With control for age, height, hours of television watched, and baseline blood pressure, systolic blood pressure increased 1.0 mm Hg in the intervention group and 2.8 mm Hg in the placebo group (effect estimate = -1.8 mm Hg; 95% confidence interval -4.0, 0.3). In black subjects the intervention effect estimate was -2.0 mm Hg (95% confidence interval -4.4, 0.4). From lowest to highest quartile of baseline calcium intake (per 1000 kcal), the intervention effect estimates were -3.5, -2.8, -1.3, and 0.0 mm Hg (p for trend = 0.009). There was little effect on diastolic blood pressure. CONCLUSION These data suggest a blood pressure-lowering effect of calcium supplementation in children, especially in subjects with low baseline calcium intake.

Epidural Analgesia and Risks of Cesarean and Operative Vaginal Deliveries in Nulliparous and Multiparous Women

Objective is to examine the effect of epidural analgesia in first stage of labor on occurrence of cesarean and operative vaginal deliveries in nulliparous women and multiparous women without a previous cesarean delivery. Design of the Prospective cohort study. Prenatal care was received at 12 free-standing health centers, 7 private physician offices, or 2 hospital-based clinics; babies were delivered at a free standing birth center or at 3 hospitals, all in San Diego, CA. This study of 2,052 women used data from the San Diego Birth Center Study that enrolled women between 1994 and 1996 to compare the birthing management of the collaborative Certified Nurse Midwife-Medical Doctor Model with that of the traditional Medical Doctor Model. Main Outcome Measures of the Cesarean or operative vaginal deliveries. After adjusting for differences between women who used and those who did not use epidural analgesia in 1st stage of labor, epidural use was associated with a 2.5 relative risk (95% CI: 1.8, 3.4) for operative vaginal delivery in nulliparous women, and a 5.9 relative risk (95% CI: 3.2, 11.1) in multiparous women. Epidural use was associated with a 2.4 relative risk (95% CI: 1.5, 3.7) for cesarean delivery in nulliparous women, and a 1.8 relative risk (95% CI: 0.6, 5.3) in multiparous women. Epidural anesthesia increases the risk for operative vaginal deliveries in both nulliparous and multiparous women, and increases risk for cesarean deliveries in nulliparous more so than in multiparous women.

Correlations of clinical and laboratory measures of balance in older men and women

It is known that impaired balance is associated with falls in older adults; however, there is no accepted gold standard on how balance should be measured. Few studies have examined measures of postural sway and clinical balance concurrently in large samples of community‐dwelling older adults. We examined the associations among 4 types of measures of laboratory‐ and clinic‐based balance in a large population‐based cohort of older adults.

Footwear and Falls in the Home Among Older Individuals in the MOBILIZE Boston Study

Background: Whether certain types of footwear, such as slippers, socks without shoes, and going barefoot, increase the risk for falls among the elderly is uncertain. Our purpose was to examine the relationship between footwear and falls within the home in MOBILIZE Boston, a prospective cohort study of falls etiology among non-institutionalized women and men, mainly aged 70 years and older, from the Boston MA, USA area. Methods: The 765 participants were from households randomly selected from town lists. They were followed for a median of 27.5 months. At baseline, participants were administered a questionnaire that included questions on footwear usually worn, and were given a comprehensive examination that included measurement of many risk factors for falls. During follow-up participants were asked to record each day whether they had fallen; those reporting falls were asked about their footwear when they fell. Results: At the time of in-home falls, 51.9% of people were barefoot, wearing socks without shoes, or wearing slippers; 10.1% of people reported that their usual footwear was one of these types. Among those who fell in their own home, the adjusted odds ratio for a serious injury among those who were shoeless or wearing slippers compared to those who were wearing other shoes at the time of the fall was 2.27 (95% confidence interval 1.21–4.24). Conclusions: It may be advisable for older individuals to wear shoes in their home whenever possible to minimize the risk of falling. Further research is needed to identify optimal footwear for falls prevention.