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Biomedical subjects

N H Wright

Publications and source records attributed to N H Wright.

At least 19 recordsLinked to original sources
PubMed1996

Risk factors for HIV-1 seroconversion among young men in northern Thailand.

OBJECTIVE: To identify behavioral and sociodemographic risk factors for incident human immunodeficiency virus-1 (HIV-1) infection among healthy young men in northern Thailand. DESIGN: Men inducted into military service in northern Thailand in May and November 1991 were followed at 6-month intervals until discharge 2 years later. Trained nonmilitary interviewers identified risk factors for HIV-1 infection through interviews with the men. SETTING: Thirteen military bases in northern Thailand. PARTICIPANTS: A total of 1932 seronegative men, aged 19 to 23 years (average age, 21 years) at enrollment, conscripted into the Royal Thai Army and Air Force from six upper-northern Thai provinces. MAIN OUTCOME MEASURES: Human immunodeficiency virus-1 seroincidence as determined through enzyme-linked immunosorbent assay and verified by Western blot, and univariate and multivariate analyses of risk factors related to HIV-1 incidence. RESULTS: A total of 85 men seroconverted to HIV-1 over the period of observation, giving an incidence rate of 2.43 per 100 person-years. Factors strongly associated with HIV-1 seroconversion were frequency of visits to female commercial sex workers (CSWs), sex with men, and incident sexually transmitted diseases (STDs). High frequency of condom use showed a significant (P < .001) protective effect for HIV-1 incidence among men with a history of recent sex with female CSWs in univariate analysis, but a multivariate model demonstrated no difference in HIV-1 seroconversion rates by consistency of condom use. Multivariate analysis incorporating condom use showed that having sex with men (adjusted relative risk [RR], 2.59; 95% confidence interval [CI], 1.08 to 6.25), having sex with CSWs (adjusted RR ranged from 2.54 [95% CI, 1.81 to 3.58] to 2.74 [95% CI, 1.56 to 4.81]), and incident STDs (adjusted RR, 2.38 [95%, CI, 1.31 to 4.32]) to be predictors of incident HIV-1 infection. Substance use was not associated with HIV-1 seroconversion rates in multivariate analysis. CONCLUSION: The HIV-1 incidence in this cohort of young men appears to be primarily attributable to having sex with female CSWs. Condom use provided some protection, although not in multivariate analysis; however, condom use has previously been shown likely to be useful in preventing HIV-1 transmission. Thus, programs to increase effective condom use in brothels are essential. Efforts to extend condom use to non-CSW partners are especially needed. More effective prevention and treatment of STDs may also be necessary to decrease HIV-1 infection in this population.

AIDS Serodiagnosis↗
PubMed1995

A computer model of health status and costs in national health planning.

We developed a computer model which measures the impact of disease on a population, has the ability to track changes in disease incidence over time, and incorporates costs of disease prevention and treatment. This model was developed with data for Malaysia and used by the Ministry of Health in the development of their national health plan. The model uses the DHLL (DALY) measure which incorporates morbidity and mortality impacts of disease. The ability of the model to adjust for changes in disease incidence over a period of years allows health planners to accurately reflect demographic and development related changes in disease incidence. This model is of value to health planners because in incorporates information on population health status, costs of prevention and treatment, and changes in health status over time. It produces an evaluation of the cost effectiveness of possible interventions that can be used by health planners in making decisions on resource allocation.

Computer Simulation↗
PubMed1994

Was the 1988 HIV epidemic among Bangkok's injecting drug users a common source outbreak?

OBJECTIVE: To describe and understand the genesis of the explosive 1988 HIV epidemic among Thai injecting drug users (IDU) in Bangkok. DESIGN: Two cross-sectional HIV seroprevalence sample surveys (SP-1 and SP-2) of drug users, including IDU at various stages of treatment. SP-1, a 10-week estimate of prevalence, was conducted by the Bangkok Metropolitan Administration (BMA) in their detoxification clinics from 5 January to 7 March 1988. SP-2 estimated prevalence in 1 week, 12-15 September 1988, in the same 18 BMA clinics. Both surveys included an administered questionnaire that gathered demographic and behavioral information. METHODS: Analysis of HIV prevalence by clinic in both SP-1 and SP-2, and the relationships between demographic data, behavioral variables, arrest history and HIV positivity in SP-1. RESULTS: Data from individual clinics in SP-1 show significant increases in HIV prevalence among IDU sampled from early February 1988. Of IDU sampled in five 'early' clinics before 9 February, 2% were positive; in the 13 'late' clinics sampled from 9 February until 7 March, 27% were positive. By September 1988, however, the early and late clinics were no longer heterogeneous for HIV prevalence. For current IDU, HIV-positivity was associated with the sharing of injection equipment in SP-1 [odds ratio (OR), 1.82; 95% confidence limits (CL), 1.31-2.53] and recent jail or prison stay (OR, 2.15; 95% CL, 1.18-3.98). CONCLUSIONS: The behavioral factors associated with the HIV epidemic among Bangkok's IDU are similar to those described elsewhere. The monthly incidence of 5% from February to September 1988 suggests extensive needle or injection equipment sharing networks among IDU in Bangkok. Additionally, the pattern of HIV-positivity by detoxification clinic over time in early 1988, and then in September 1988 is consistent with a relationship to the prison amnesty of early December 1987. Shortly after that date, an undisclosed number of former IDU, a substantial number of whom were still injecting, and may have become HIV-positive while in custody, returned to resume injecting within existing drug-using networks throughout Bangkok and elsewhere in Thailand.

Adolescent↗
PubMed1994

HIV-1 infection among lower class commercial sex workers in Chiang Mai, Thailand.

OBJECTIVE: To determine risk factors for HIV-1 infection in female commercial sex workers (CSW) in northern Thailand. METHODS: A cross-sectional survey of female CSW from 11 sex establishments frequented by military conscripts that included an interview and serological testing for HIV-1. RESULTS: The HIV-1 seroprevalence in 230 CSW was 65%; the rate was lower among CSW from Chiang Mai than from rural areas. Multivariate logistic regression analysis for HIV-1 included the following significant factors: non-urban location of the sex establishment, ethnic Thai lowlander, lower price, history of genital warts and dysuria. Condom use, number of partners and duration of employment were not significantly associated with HIV-1 prevalence after adjustment for other risk factors. CONCLUSIONS: The high level of HIV-1 seroprevalence in this sample demonstrates the risk of transmission in lower cost commercial sex encounters in northern Thailand. Non-Thais (ethnic Hill tribes and Burmese) had lower HIV-1 prevalence than ethnic Thais. Type of establishment ('direct' brothel-based or 'indirect' establishments) was not predictive of HIV-1 seroprevalence. However, rural establishments were less vigilant in promoting condom use, suggesting the need for renewed efforts to enforce the Ministry of Public Health's '100% Condom Campaign' in commercial sex establishments.

Adolescent↗
PubMed1991

Risk factor changes after cessation of intervention in the Multiple Risk Factor Intervention Trial. The MRFIT Research Group.

BACKGROUND: The degree of maintenance of risk factor changes observed in post-trial follow-up of participants in the Multiple Risk Factor Intervention Trial (MRFIT) provides insights into long-term determinants of preventive behaviors, as well as post-trial mortality differentials. METHODS: Nine hundred eighty-nine former MRFIT participants at four clinical centers were invited to be reexamined 2-3.5 years after the end of this 6- to 8-year trial. Seventy percent came to the clinics for measurements of systolic and diastolic blood pressure, plasma lipids and lipoproteins, serum thiocyanate, and dietary food frequency. With the addition of phone interviews, 82% provided self-report data on cigarette smoking and use of antihypertensive drugs. RESULTS: Comparison of Special Intervention (SI) and Usual Care (UC) groups showed that differences persisted for total (6.5 mg/dl, P = 0.02) and low-density lipoprotein cholesterol (5.4 mg/dl, P = 0.04), and for diastolic blood pressure (1.6 mm Hg, P = 0.02). Differences were not significant for systolic blood pressure (1.8 mm Hg, P = 0.12), cigarette smoking, and serum thiocyanate. The plasma cholesterol difference represented 70% of the value at the end of intervention, and food frequency profiles were consistent with maintenance of an SI - UC difference. Loss of the SI - UC difference in smoking was attributable to both UC cessation and SI recidivism. The blood pressure difference was not attributable to different proportions of SI and UC men on medications, but possibly to differences in diuretic doses, use of multiple drugs, and adherence. There was a persisting contrast in use of specific diuretics, with more frequent use of chlorthalidone and less of hydrochlorothiazide in the SI group. CONCLUSION: These findings suggest that cholesterol-lowering dietary changes are self-sustaining, while smoking cessation is less so, and may require continued intervention. Finally, the SI - UC differences in use of specific diuretics remains one hypothesis for explaining a portion of post-trial mortality trends.

Adult↗
PubMed1991

AIDS beliefs and behaviors among intravenous drug users in Bangkok.

Prompted by an explosive epidemic of HIV-1 in early 1988 among Thai IVDUs under treatment for heroin use, a series of focus group discussions were conducted at six Bangkok detoxification clinics. In developing qualitative information on knowledge of and attitudes toward AIDS, and on drug use and sexual behavior, our objectives were to identify intervention measures, develop culturally-appropriate educational material, strengthen counseling, and sharpen the focus of needed quantitative research. An abundant store of diverse anecdotal responses and reactions emerged. We discuss the reliability and the policy and research implications of these findings.

Acquired Immunodeficiency Syndrome↗
PubMed1981

A case-control study of the possible association between oral contraceptives and malignant melanoma.

In a case-control study, we investigated 169 women aged 15-49 years with malignant melanoma notified to the Oxford and South Western cancer registries during the years 1971-1976, together with 507 matched controls. Data about medical, reproductive, drug and smoking histories were obtained both by reviewing general practitioner (GP) records and from the women themselves by postal questionnaires. There was no significant evidence of any overall increase in the risk of melanoma in oral contraceptive (OC) users (data from GP records-ever use vs never use, relative risk (RR) 1.34, 95% confidence limits 0.92-1.96; corresponding data from postal questionnaires-RR 1.13, limits 0.73-1.75). However, although not significant, the risk estimated from data in the postal questionnaires was higher in women who had used OCs for 5 years or more (use greater than or equal to 5 years vs never use, RR 1.57, limits 0.83-3.03). Previously demonstrated risk factors for melanoma, such as fair skin, blond or red hair and Celtic origin were found to be commoner in the cases than in the controls. Data from the Oxford/Family Planning Association contraceptive study were also examined. Unexpectedly there was a strong suggestion of a negative association between OC use and melanoma risk, but the analysis was based on only 12 women with the disease.

Adolescent↗
PubMed1978

Fertility after stopping different methods of contraception.

Data on the return of fertility after discontinuing various methods of contraception were collected from among the women taking part in the Oxford-Family Planning Association contraceptive study. Return of fertility was measured as the time taken to give birth to a child. The fertility of both nulligravid and parous women who stopped taking oral contraceptives was initially impaired in comparison with that of women who stopped using other methods of contraception. But the effect of oral contraceptives on fertility had become negligible by 42 months after cessation of contraception in nulligravidae and by 30 months in multiparae. Impairment seemed to be independent of the length of use of oral contraceptives. Data relating to IUD users were sparse, but the figures that were available were reassuring. These results suggest that, although women may have temporary impairment of fertility after discontinuing oral contraception, they are unlikely to become permanently sterile through taking the pill.

Adult↗
PubMed1978

Neoplasia and dysplasia of the cervix uteri and contraception: a possible protective effect of the diaphragm.

Among the 17,032 women included in the Oxford-Family Planning Association contraceptive study, 65 developed biopsy proven cervical neoplasia (including dysplasia) prior to 1 September 1977. The incidence rate in diaphragm users (0.17 per 1000 woman-years of observation) was much lower than the rates in oral contraceptive users or intrauterine device users (0.95 and 0.87 respectively). This difference could not be explained in terms of confounding variables, nor was it attributable to a lower frequency of cervical smearing among diaphragm users within the clinics. Detailed information about age at first intercourse, numbers of sexual partners and the frequency of cervical smearing outside the clinics was obtained from 52 of the women with cervical neoplasia and 139 matched controls. Diaphragm users were less likely to have had coitus at an early age and had had materially fewer sexual partners than users of the other two methods of contraception. After adjusting for the effects of these variables, however, the risk of cervical neoplasia in diaphragm users was still only about one quarter that in the users of the other methods. Patterns of smearing varied little between users of the various contraceptive methods. Smoking emerged as a major "risk factor" for cervical neoplasia in this study. This probably implies that the smoking habit reflects some important aspect of sexual behaviour relevant to the production of the disease that we have been unable to measure.

Adult↗
PubMed1977

Nurse-midwife insertion of the copper T in Thailand: performance, acceptance, and programmatic effects.

While oral contraceptives have been widely available in rural Thailand since their distribution by lower level paramedical health workers was authorized in 1970, the IUD has been restricted to large, urban clinics staffed by physicians. A study was conducted in 1972-73 to evaluate the performance of nurse-midwives in IUD (Copper T) insertion and to assess the reaction of acceptors and the likely effects on the National Family Planning Program. It was found that nurse-midwives were competent to insert Copper Ts and handle early complications. Acceptor continuation rates were very high and nurse-midwife acceptors clearly preferred IUD insertion by a female health worker. Programmatic evidence suggests that using nurse-midwives more extensively for Copper T insertion would increase IUD acceptance at no cost to the existing loop program.

Adolescent↗
PubMed1977

Attitudes toward abortion in Thailand: a survey of senior medical students.

A majority of senior Thai medical students favored induced abortion in many circumstances not now considered legal. While 20 percent would not perform abortions for any reason, many of these would refer cases to colleagues. Independent variables consistently and significantly influencing attitudes conservatively were: female sex, certain medical schools attended, larger ideal family size, intention not to teach in a medical school as a career, having a father in unskilled or semiskilled or work, never having witnessed an illegal abortion, and never having been asked to find an abortion practitioner for a friend. A random reordering of the questions did not affect reports of attitudes toward or willingness to perform induced abortion.

Abortion, Illegal↗
PubMed1975

Restricting legal abortion: Some maternal and child health effects in Romania.

The dramatic rise of the Romanian birth rate in 1967 following the restrictive abortion decree of late 1966 is well known. Less well known are significant changes in key maternal and child health indicators in the period after 1966. Possible reasons for these changes are discussed as are the implications of the Romanian experience for population policy and abortion research in the United States.

Abortion, Legal↗