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Biomedical subjects

R H Gray

Publications and source records attributed to R H Gray.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effect of continuing or stopping smoking during pregnancy on infant birth weight, crown-heel length, head circumference, ponderal index, and brain:body weight ratio.

The objective of this study was to determine whether stopping smoking between the first prenatal care visit and the 32nd week of pregnancy affects the smoking-associated changes in five infant anthropometric indices. The study population consisted of 15,185 births in the Swedish Medical Birth Register from 1991 and 1992. The associations between birth weight, crown-heel length, head circumference, ponderal index, brain:body weight ratio, maternal smoking status at the first prenatal care visit and at 32 weeks' gestation, and other maternal and infant characteristics were assessed using multivariate linear regression. The infants of 946 women who stopped smoking before week 32 of pregnancy were statistically indistinguishable from the 9,802 infants of nondaily smokers in terms of birth weight, head circumference, and brain:body weight ratio, but they retained a significant deficit in crown-heel length of 0.23 cm (standard error, 0.08) and a significant elevation in ponderal index of 0.027 (standard error, 0.009). In this study, stopping smoking between the first prenatal care visit and week 32 of pregnancy prevented smoking-associated deficits in infant birth weight, head circumference, and brain:body weight ratio, but did not completely prevent deficits in crown-heel length in comparison with nonsmokers' infants of the same age, and did not prevent elevation of ponderal index in comparison with nonsmokers' infants of the same weight and age.

Adult↗
PubMed2000

Duration of human immunodeficiency virus infection and likelihood of giving birth in a Medicaid population in Maryland.

The objective of this study was to examine the effect of duration of human immunodeficiency virus (HIV) infection on a woman's likelihood of giving birth. Using longitudinal data from the Maryland state Human Immunodeficiency Virus Information System and a retrospective cohort design, the authors compared 1,642 women with acquired immunodeficiency syndrome (AIDS) to 8,443 uninfected women enrolled in the Medicaid program between 1985 and 1995. The decade before AIDS diagnosis was divided into four 2.5-year periods. Proximity to AIDS diagnosis served as a proxy for duration of infection. An extension of the Cox model was used to estimate the relative risk for giving birth, with adjustment for covariates and repeated outcomes. The average number of births per 100 person-years was 6.0 for HIV-infected women and 11.1 for uninfected women (adjusted relative risk = 0.63; 95% confidence interval (CI): 0.57, 0.68). Accounting for duration of infection, the adjusted relative risks for birth among HIV-infected women, as compared with uninfected women, were 0.85 (95% CI: 0.71, 1.03), 0.74 (95% CI: 0.63, 0.86), 0.55 (95% CI: 0.47, 0.64), and 0.45 (95% CI: 0.38, 0.55) for successive 2.5-year periods before AIDS diagnosis. Demographic characteristics, contraception, abortion, fetal loss, or drug use could not fully explain the reductions. These results suggest that HIV-infected women experience a progressive reduction in births years before the onset of AIDS. This may compromise estimation of HIV prevalence and interpretation of time trends from serosurveillance of pregnant women.

Adolescent↗
PubMed2000

Viral load and heterosexual transmission of human immunodeficiency virus type 1. Rakai Project Study Group.

BACKGROUND AND METHODS: We examined the influence of viral load in relation to other risk factors for the heterosexual transmission of human immunodeficiency virus type 1 (HIV-1). In a community-based study of 15,127 persons in a rural district of Uganda, we identified 415 couples in which one partner was HIV-1-positive and one was initially HIV-1-negative and followed them prospectively for up to 30 months. The incidence of HIV-1 infection per 100 person-years among the initially seronegative partners was examined in relation to behavioral and biologic variables. RESULTS: The male partner was HIV-1-positive in 228 couples, and the female partner was HIV-1-positive in 187 couples. Ninety of the 415 initially HIV-1-negative partners seroconverted (incidence, 11.8 per 100 person-years). The rate of male-to-female transmission was not significantly different from the rate of female-to-male transmission (12.0 per 100 person-years vs. 11.6 per 100 person-years). The incidence of seroconversion was highest among the partners who were 15 to 19 years of age (15.3 per 100 person-years). The incidence was 16.7 per 100 person-years among 137 uncircumcised male partners, whereas there were no seroconversions among the 50 circumcised male partners (P<0.001). The mean serum HIV-1 RNA level was significantly higher among HIV-1-positive subjects whose partners seroconverted than among those whose partners did not seroconvert (90,254 copies per milliliter vs. 38,029 copies per milliliter, P=0.01). There were no instances of transmission among the 51 subjects with serum HIV-1 RNA levels of less than 1500 copies per milliliter; there was a significant dose-response relation of increased transmission with increasing viral load. In multivariate analyses of log-transformed HIV-1 RNA levels, each log increment in the viral load was associated with a rate ratio of 2.45 for seroconversion (95 percent confidence interval, 1.85 to 3.26). CONCLUSIONS: The viral load is the chief predictor of the risk of heterosexual transmission of HIV-1, and transmission is rare among persons with levels of less than 1500 copies of HIV-1 RNA per milliliter.

Adolescent↗
PubMed2000

Classification criteria and severity assessment in work-associated upper extremity disorders: methods matter.

Work-associated musculoskeletal disorders of the upper extremity are common and disabling. Research on these disorders is needed and requires valid methods of classification of the disorders for epidemiologic studies and measurement of their impact on functional status. This commentary discusses the methodologic aspects of classification and functional status assessment in upper extremity musculoskeletal disorders.

Classification↗
PubMed2000

Rapid onset retinopathy in a diabetic patient following bone marrow transplantation.

We report a 38-year-old man who presented in 1998 with advanced multiple myeloma and newly diagnosed diabetes mellitus (DM). Subsequent BMT has been successful after conditioning with melphalan and total body irradiation, but significant ischaemic retinopathy has developed. Chemotherapeutic agents, total body irradiation, and DM are likely to have been co-factors in precipitating the rapid onset of retinopathy. Routine ophthalmic surveillance is recommended for all patients after BMT, particularly for those with additional risk factors for the development of retinopathy such as DM.

Adult↗
PubMed2000

Selected topics in the epidemiology of reproductive outcomes.

In summary, progress in research on reproductive epidemiology will depend on the increased use of biologic measurement, a focus on multiple outcomes, and an increased use of the couple or sexual network as the unit of study, with appropriate statistical methods for analysis of correlated data. The combination of these approaches holds great promise for research in the 21st century.

Biomarkers↗
PubMed2000

Trends and determinants of contraceptive use in Rakai District, Uganda, 1995-98.

A prospective study conducted between 1995 and 1998 assessed trends in contraceptive use in rural Rakai District, Uganda. Over a period of 30 months, women's use of modern contraceptives increased significantly from 11 percent to 20 percent. Male condom use increased from 10 percent to 17 percent. The prevalence of pregnancy among sexually active women 15-49 declined significantly from 15 percent to 13 percent. Women practicing family planning for pregnancy prevention were predominantly in the 20-39-year age group, married, better educated, and had higher parity than others, whereas women or men adopting condoms were predominantly young, unmarried, and better educated. Condom use was particularly high among individuals reporting multiple sexual partners or extramarital relationships. Contraceptive use was higher among women who desired fewer children, among those who wished to space or terminate childbearing, and among women with previous experience of unwanted births or abortions. Self-perception of HIV risk increased condom use, but HIV testing and counseling had only modest effects. Contraception for pregnancy prevention and for HIV/STD prophylaxis are complementary.

Abortion, Induced↗
PubMed2000

Genital tract infections and perinatal transmission of HIV.

In areas of the world where genital tract infections (GTIs) are common, the prevalence of HIV and the rate of mother-to-child transmission (MTCT) of HIV are also high. Although observational studies suggested that GTIs are associated with MTCT of HIV, no controlled clinical trial has confirmed this finding. It is likely that GTIs that cause either discharges or ulcers during pregnancy increase perinatal transmission of HIV. Several potential biological mechanisms might facilitate perinatal transmission. For example, chorioamnionitis, increased viral shedding in cervicovaginal secretions, increased HIV acquisition during pregnancy, inflammatory cytokine production, preterm labor, prolonged rupture of membranes, ascending infection, and increased intrapartum infectious secretions are factors that can be associated with GTIs. Several studies have shown that treating clinical conditions associated with inflammation might alter HIV shedding. It is conceivable that preventing ascending infection or reducing exposure of the infant to infectious material during birth could reduce MTCT. This can possibly be achieved by antimicrobial therapy during pregnancy and intrapartum. Such an approach is practical, is less expensive, and has secondary benefits related to prevention of adverse pregnancy outcomes associated with GTIs. Antibiotics might also complement reductions in MTCT of HIV obtained by antiretrovirals given to the mother around the time of delivery. In addition, antibiotics could reduce infectious causes of morbidity and mortality in infant and mother.

Female↗
PubMed2000

Maternal cigarette smoking during pregnancy and infant ponderal index at birth in the Swedish Medical Birth Register, 1991-1992.

OBJECTIVES: This study examined the effect of maternal smoking during pregnancy on infant body proportion. METHODS: The ponderal index, defined as birthweight divided by crown-heel length cubed, was examined in 207,607 infants from the Swedish Medical Birth Register for 1991 and 1992. RESULTS: Infant ponderal index was used as the outcome variable in an ordinary least squares continuous regression, which included early pregnancy smoking status, gestational age, and birthweight among the predictors. Ponderal index increased by 0.030 (+/- 0.0014) among infants of moderate smokers and by 0.040 (+/- 0.0017) among infants of heavy smokers, showing a dose response. CONCLUSIONS: Smoking differentially alters the trajectory of weight vs length growth in the fetus.

Adult↗
PubMed2000

Subfertility and risk of spontaneous abortion.

OBJECTIVES: The purpose of this study was to assess the association between subfertility and spontaneous abortion. METHODS: A total of 1572 women in New York and Vermont reported 3269 pregnancies between 1980 and 1990 and were able to provide an estimate of the waiting time to conception for 2967. Subfertility was defined as a delay of 1 year or more before a recognized conception was achieved. Rates of spontaneous abortion were determined among women with and without subfertility, and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated via multiple logistic regression. RESULTS: Spontaneous abortion rates were 23.0% in pregnancies preceded by subfertility and 14.0% in pregnancies without impaired fertility (adjusted OR = 1.71, 95% CI = 1.26, 2.94). The attributable risk of spontaneous abortion associated with subfertility was 6.2%. CONCLUSIONS: Subfertile women evidence an increased number of spontaneous abortions.

Abortion, Spontaneous↗
PubMed2000

Sero-prevalence of Herpes simplex virus type 2 (HSV-2) in Rakai district, Uganda.

BACKGROUND: Herpes simplex virus type 2 (HSV-2) is sexually transmitted and causes one of the genital ulcerative diseases associated with the transmission of human immunodeficiency virus type I (HIV-1). OBJECTIVE: To determine the prevalence of serological reactivity to a type specific HSV-2 antigen (gG2) ELISA assay. SETTING: Rakai district, Uganda. SUBJECTS: Two hundred and one serum samples of persons aged 15-54 years. The samples were randomly selected by a computer programme. RESULTS: Out of the 201 serum samples selected, 117 (58.2%) had serological evidence of HSV-2 infection. Twenty nine (32.2%) out of the 74 males and 88 (69.3%) out of the 127 females, respectively, had serological evidence of HSV-2 infection giving a female:male ratio of 1.8 (95% CI 1.3-2.4). The most important risk factor for acquisition of HSV-2 in males was found to be age while in the females, the most important risk factors were age and the number of sexual partners in the previous five years. CONCLUSION: HSV-2 was highly prevalent in this rural population of Uganda.

Adolescent↗
PubMed1999

Placental membrane inflammation and risks of maternal-to-child transmission of HIV-1 in Uganda.

UNLABELLED: Prospective follow-up of 172 HIV-infected pregnant women and their infants was conducted at Mulago Hospital, Kampala, Uganda during 1990 to 1992. Information was collected on maternal immune status (CD4 counts or clinical AIDS), and concurrent infections with sexually transmitted diseases. Infants were observed on a follow-up basis to determine HIV infection, using polymerase chain reaction (PCR) under 15 months of age and enzyme immunoassay/Western blot for those older than 15 months. Placental membrane inflammation (chorioamnionitis and funisitis), and placental villous inflammation (villitis, intervillitis, and deciduitis) were diagnosed by histopathology. Mother-to-child HIV transmission rates were assessed, and adjusted odds ratios (OR) and 95% confidence intervals (95% CI) of transmission were estimated using women with no placental pathology or evidence of immune suppression as a reference group. RESULTS: The overall mother-to-child HIV transmission rate was 23.3%. Women with no placental membrane inflammation or immune suppression had a transmission rate of 11.3%; compared with 25.5% in women with placental inflammation and no immunosuppression (adjusted OR, 2.87; 95% CI, 1.04-7.90), and 37.0% in immunosuppressed women (OR, 3.07; 95% CI, 1.42-6.67). We estimate that 34% of HIV transmission could be prevented by treatment of placental membrane inflammation in nonimmunocompromised women. Transmission rates were 40.9% with genital ulcer disease (OR, 3.57; 95% CI, 1.28-9.66). Placental villous inflammation and artificial rupture of membranes did not increase transmission rates and cesarean section was associated with a nonsignificant reduction of risk (OR, 0.70; 95% CI 0.24-2.06). CONCLUSION: Placental membrane inflammation increases the rate of mother-to-child HIV transmission.

Blotting, Western↗
PubMed1999

Relative risks and population attributable fraction of incident HIV associated with symptoms of sexually transmitted diseases and treatable symptomatic sexually transmitted diseases in Rakai District, Uganda. Rakai Project Team.

OBJECTIVES: To assess the linkage of sexually transmitted disease (STD) symptoms and treatable STD to HIV incidence. DESIGN: Analysis of a randomized trial of STD control for HIV prevention, Rakai, Uganda. METHODS: Consenting adults 15-59 years of age were seen at 10-monthly home visits, interviewed regarding STD symptoms, and asked to provide samples for HIV and STD diagnoses. HIV incidence was determined in 8089 HIV-negative subjects over 10 457 person years. Adjusted rate ratios (RR) and 95% confidence intervals (CI) of HIV acquisition associated with genital ulcer disease (GUD) and discharge/dysuria were used to estimate the population attributable fraction (PAF) of HIV acquisition. HIV transmission risks associated with STD symptoms in HIV-positive partners of 167 HIV discordant couples and the numbers of sexual partners reported by HIV-positive subjects were used to estimate the PAF of HIV transmission attributable to STD. RESULTS: HIV prevalence was 16%. The risk of HIV acquisition was increased with GUD (RR 3.14; CI 1.98-4.98) and in males with discharge/dysuria (RR 2.44; CI 1.17-5.12), but not in females with discharge/dysuria. The PAF of HIV acquisition was 9.5% (CI 2.8-15.8%) with any of the three STD symptoms. The PAF for GUD was 8.8% (CI 3.7-13.8), but only 8.2% of reported GUD was caused by treatable syphilis or chancroid . The PAF for discharge/dysuria in males was 6.7% (CI 1.1-13.8), but only 25% of symptomatic males had concurrent gonorrhea or chlamydial infection. No significant differences were seen in PAF between study treatment arms. The PAF of HIV transmission associated with STD symptoms in HIV-positive persons was indirectly estimated to be 10.4%. CONCLUSION: In this mature, generalized HIV epidemic setting, most HIV seroconversion occurs without recognized STD symptoms or curable STD detected by screening. Therefore, syndromic management or other strategies of STD treatment are unlikely to substantially reduce HIV incidence in this population. However, STD is associated with significant HIV risk at the individual level, and STD management is needed to protect individuals.

Adolescent↗
PubMed1999

Age of male circumcision and risk of prevalent HIV infection in rural Uganda.

OBJECTIVE: To assess whether circumcision performed on postpubertal men affords the same level of protection from HIV-1 acquisition as circumcisions earlier in childhood. DESIGN: Cross-sectional study of a population-based cohort. SETTING: Rakai district, rural Uganda. METHODS: A total of 6821 men aged 15-59 years were surveyed and venous blood samples were tested for HIV-1 and syphilis. Age at circumcision was dichotomized into men who were circumcised before or at age 12 years (prepubertal) and men circumcised after age 12 years (postpubertal). Postpubertal circumcised men were also subdivided into those reporting circumcision at ages 13-20 years and > or = 21 years. RESULTS: HIV-1 prevalence was 14.1% in uncircumcised men, compared with 16.2% for men circumcised at age > or = 21 years, 10.0% for men circumcised at age 13-20 years, and 6.9% in men circumcised at age < or = 12 years. On bivariate analysis, lower prevalence of HIV-1 associated with prepubertal circumcision was observed in all age, education, ethnic and religious groups. Multivariate adjusted odds ratio of prevalent HIV-1 infection associated with prepubertal circumcision was 0.39 [95% confidence interval (CI), 0.29-0.53]. In the postpubertal group, the adjusted odds ratio for men circumcised at ages 13-20 years was 0.46 (95% CI, 0.28-0.77), and 0.78 (95% CI, 0.43-1.43) for men circumcised after age 20 years. CONCLUSIONS: Prepubertal circumcision is associated with reduced HIV risk, whereas circumcision after age 20 years is not significantly protective against HIV-1 infection. Age at circumcision and reasons for circumcision need to be considered in future studies of circumcision and HIV risk.

Adolescent↗
PubMed1999

Control of sexually transmitted diseases for AIDS prevention in Uganda: a randomised community trial. Rakai Project Study Group.

BACKGROUND: The study tested the hypothesis that community-level control of sexually transmitted disease (STD) would result in lower incidence of HIV-1 infection in comparison with control communities. METHODS: This randomised, controlled, single-masked, community-based trial of intensive STD control, via home-based mass antibiotic treatment, took place in Rakai District, Uganda. Ten community clusters were randomly assigned to intervention or control groups. All consenting residents aged 15-59 years were enrolled; visited in the home every 10 months; interviewed; asked to provide biological samples for assessment of HIV-1 infection and STDs; and were provided with mass treatment (azithromycin, ciprofloxacin, metronidazole in the intervention group, vitamins/anthelmintic drug in the control). Intention-to-treat analyses used multivariate, paired, cluster-adjusted rate ratios. FINDINGS: The baseline prevalence of HIV-1 infection was 15.9%. 6602 HIV-1-negative individuals were enrolled in the intervention group and 6124 in the control group. 75.0% of intervention-group and 72.6% of control-group participants provided at least one follow-up sample for HIV-1 testing. At enrolment, the two treatment groups were similar in STD prevalence rates. At 20-month follow-up, the prevalences of syphilis (352/6238 [5.6%]) vs 359/5284 [6.8%]; rate ratio 0.80 [95% CI 0.71-0.89]) and trichomoniasis (182/1968 [9.3%] vs 261/1815 [14.4%]; rate ratio 0.59 [0.38-0.91]) were significantly lower in the intervention group than in the control group. The incidence of HIV-1 infection was 1.5 per 100 person-years in both groups (rate ratio 0.97 [0.81-1.16]). In pregnant women, the follow-up prevalences of trichomoniasis, bacterial vaginosis, gonorrhoea, and chlamydia infection were significantly lower in the intervention group than in the control group. No effect of the intervention on incidence of HIV-1 infection was observed in pregnant women or in stratified analyses. INTERPRETATION: We observed no effect of the STD intervention on the incidence of HIV-1 infection. In the Rakai population, a substantial proportion of HIV-1 acquisition appears to occur independently of treatable STD cofactors.

Acquired Immunodeficiency Syndrome↗
PubMed1999

HIV infection and disturbances of vaginal flora during pregnancy.

Disturbances of vaginal flora are common among women of reproductive age. In areas of sub-Saharan Africa where the prevalence of HIV is high, the frequency of bacterial vaginosis (BV) is also high. In this study, we assessed the association of BV and other disturbances of vaginal flora with prevalent HIV infection in two cross-sectional studies among pregnant women in urban Malawi. The prevalence of HIV-1 was 23% in 1990 and 30% in 1993. Overall, 30% of the women had BV, 59% had mild or moderate disturbance of vaginal flora, and only 11% had normal vaginal flora. Increasing prevalence of HIV was significantly associated with increasing severity of disturbance of vaginal flora (p < .00001, chi2 trend test). This trend of increased prevalence persisted after controlling for concurrent sexually transmitted diseases (STDs), sexual activity, and socioeconomic factors. After multivariate adjustment for potential confounders, the odds ratio for the association of BV with prevalent HIV infection was 3.0 (95% confidence interval [CI], 2.4-3.8), that of moderate vaginal disturbance with HIV infection was 2.2 (95% CI, 1.7-2.8), and that of mild vaginal disturbance with HIV infection was 1.6 (95% CI, 1.3-2.1). Among women with BV, HIV infection was higher among younger women than older, implying more recent infection. Although these studies were cross-sectional, our data suggest that BV could be associated with increased susceptibility to HIV infection.

Adult↗