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Biomedical subjects

P Byass

Publications and source records attributed to P Byass.

At least 19 recordsLinked to original sources
PubMed2006

Association between body mass index and blood pressure across three populations in Africa and Asia.

Despite a growing burden of obesity and hypertension in developing countries, there is limited information on the contribution of body mass index (BMI) to blood pressure (BP) in these populations. This study examines the association between BMI and BP in three populations across Africa and Asia. Data on BMI, BP and other background characteristics of study participants were generated using the World Health Organization STEPwise approach to surveillance (STEPS), at three demographic surveillance sites in Ethiopia, Vietnam and Indonesia. BMI and BP increased along the socioeconomic gradient across the three countries. Mean (s.d.) BMI in men varied between 19.41 (2.28) in Ethiopia to 21.17 (2.86) in Indonesia. A high prevalence of overweight/obesity was noted among Indonesian women (25%) and men (10%), whereas low BMI was widely prevalent in Ethiopia and Vietnam, ranging from 33 to 43%. Mean (s.d.) systolic BP (SBP) among men varied between 117.15 (15.35) in Ethiopia to 127.33 (17.80) in Indonesia. The prevalence of hypertension was highest among women (25%) and men (24%) in Indonesia. Mean BP levels increased with increasing BMI. The risk of hypertension was higher among population groups with overweight and obesity (BMI>/=25 kg/m(2)); odds ratio (95% confidence interval); 2.47 (1.42, 4.29) in Ethiopia, 2.67 (1.75, 4.08) in Vietnam and 7.64 (3.88, 15.0) in Indonesia. BMI was significantly and positively correlated with both SBP and DBP in all the three populations, correlation coefficient (r) ranging between 0.23 and 0.27, P<0.01. High BP exists in a background of undernutrition in populations at early stages of the epidemiologic transition.

Adult↗
PubMed2006

Gender differences in prevalence and socioeconomic determinants of hypertension: findings from the WHO STEPs survey in a rural community of Vietnam.

In Vietnam, hypertension was estimated to cause a large number of deaths in hospitals. However, population-based knowledge about the magnitude of hypertension in Vietnam and its relationship with socioeconomic status, especially in the rural communities, still remains scarce. This paper, taking advantage of a study on noncommunicable disease (NCD) risk factors in Bavi district, Vietnam, using the WHO STEPs approach, estimates the prevalence of hypertension in the setting and examines its association with some socioeconomic factors. A representative sample comprising 2000 adults aged 25-64 years were selected randomly and surveyed in 2002. The JNC VII criteria for hypertension were used. Socioeconomic status of the study subjects was estimated by assessing their education, occupation and economic conditions. Descriptive techniques and multivariate logistic regression were used. The prevalence of hypertension was 14.1%. Of hypertensives, only 17.4% were aware of their hypertensive status. Men were hypertensive more often than women and age was positively associated with hypertension. The association between hypertension and socioeconomic status was complex and differed between men and women. Among men, those with lower educational and occupational status but who were richer were more likely to be hypertensive. More women with lower occupational and economic status were hypertensive.

Adult↗
PubMed2005

Unintentional injuries over a 1-year period in a rural Vietnamese community: describing an iceberg.

OBJECTIVES: To document unintentional injuries in a rural community over a 1-year period as a basis for prioritizing preventive activities. STUDY DESIGN: Quarterly home visits over 1 year to elicit experience of injury among household members in the preceding 3 months. METHODS: In total, 24,776 people living in rural communities in the Bavi District, Northern Vietnam, were surveyed in home visits during 2000. In the home visits, injuries that needed care or disrupted normal activities were recorded, together with their circumstances. RESULTS: Overall, 2079 new non-fatal injuries were recorded over 23,338 person-years, a rate of 89/1000 person-years-at-risk. Males had a significantly higher injury rate than females for all age groups except for those aged 35-59 years and the elderly (P<0.05). The elderly were at highest risk of injury (P<0.05), particularly females. Home injuries occurred at the highest overall rate, particularly among the elderly. Road traffic injuries were most common among children. Most injuries involved contact with another object. Less than one-quarter of injury victims sought care at a health facility. CONCLUSIONS: Community-based household surveys revealed the hidden part of the injury iceberg, as well as showing high incidence rates, indicating that injury is an important public health problem which should be a priority for intervention in rural Vietnam, and probably elsewhere. This comprehensive study is intended to contribute evidence and methods to the Ministry of Health's national programme for injury prevention, and to a wider audience.

Adolescent↗
PubMed2003

Empirical modelling of population sampling: lessons for designing sentinel surveillance.

BACKGROUND: In order to consider the practical viability of 1% sentinel area surveillance for health information in resource-poor settings where complete registration is unrealistic, the effects of different sampling procedures on the representativeness of 1% population samples have been investigated. METHODS: Using the 1991 census of England as a basis for modelling, 20 1% samples, each incorporating seven key parameters, were drawn at random from the overall dataset by each of eight different sampling procedures. Each sample was compared with the 'gold standard' of the overall census results, enabling comparisons between the different sampling procedures. RESULTS: Representativeness of the 1% samples varied considerably between parameters and sampling procedures. At one extreme, the proportion of males in the population was distributed such that different sampling methods had little effect. On the other hand, samples of a heterogeneous parameter such as the proportion of non-whites in the population depended greatly on the procedure used. Sampling smaller administrative units tended to be more accurate. However, sampling units using probability proportional to size generally gave less representative samples. Stratifying urban and rural populations in the samples had little effect. Multistage sampling, emulating typical demographic surveillance sites, also generally gave less representative samples. CONCLUSIONS: It is possible to achieve representative data by taking 1% of a national population in a sentinel surveillance approach, but sampling design can have an important influence on the outcome. This modelling supports the concept of 1% sentinel surveillance for health information in poorer settings, where complete data are unavailable.

Censuses↗
PubMed2002

The role of demographic surveillance systems (DSS) in assessing the health of communities: an example from rural Ethiopia.

Longitudinal demographic surveillance systems (DSSs) in selected populations can provide important information in situations where routine health information is incomplete or absent, particularly in developing countries. The Butajira Rural Health Project is one such example, initiated in rural Ethiopia in 1987. DSSs rely on regular community-based surveillance as a means of vital event registration, among a sufficient population base to draw meaningful conclusions about rates and trends in relatively rare events such as maternal death. Enquiries into specific health problems can also then use this framework to quantify particular issues or evaluate interventions. Demographic characteristics and trends for a rural Ethiopian population over a 10-y period are presented as an illustration of the DSS approach, based on 336 000 person-years observed. Overall life expectancy at birth was 50 y. Demographic parameters generally showed modest trends towards improvement over the 10-y period. The DSS approach is useful in characterising populations at the community level over a period of time, providing important information for health planning and intervention. Methodological issues underlying this approach need further exploration and development.

Adolescent↗
PubMed2002

Schistosome transmission, water-resource development and altitude in northern Ethiopia.

Schistosomiasis continues to be a major public-health problem, not least in association with water-resource developments. The impact of microdam construction in the northern Ethiopian highlands, in relation to possible increased risks of Schistosoma mansoni infection, has now been assessed. The results of incidence studies, carried out on 473 individuals sampled across eight microdam sites at altitudes of 1800-2225 m above sea level, indicated an overall annual incidence of 0.20 infections/person at risk. A multivariate Poisson regression model showed altitude and sex to be significant risk factors for infection, whereas proximity to a microdam was not significant, except possibly at very high altitudes. It was concluded that altitude was the major factor in this environment and that therefore, at least in terms of public-health planning, microdams should be sited as high as local geography permits.

Adolescent↗
PubMed2000

Prior BCG vaccination improves survival of Gambian patients treated for pulmonary tuberculosis.

The protection provided by BCG against pulmonary tuberculosis ranges from nil to over 90%. While BCG protects against the more serious forms of tuberculosis, it is not known whether or not it protects patients with pulmonary tuberculosis from death. In a study designed to look at the effects of immunotherapy with M. vaccae as an adjunct to chemotherapy in 285 adult Gambian patients treated for proven pulmonary tuberculosis, we examined the association between the presence or absence of a BCG scar and mortality. The data showed that subjects who had a BCG scar were significantly younger than those who did not, and were less likely to have nutritional oedema. During the course of treatment, none of the 85 patients who had a BCG scar died compared to 35 of 200 patients (17.5%) who did not (P < 0.001). In these Gambian patients with pulmonary tuberculosis, prior vaccination with BCG may have provided substantial protection against death. However, there is the possibility that this finding is the result of confounding by other factors or has arisen from bias. Researchers with similar data need to investigate this question as this association, if true, could have major implications for BCG vaccination.

Adolescent↗
PubMed2000

The ALERT MDT Field Evaluation Study (AMFES): a descriptive study of leprosy in Ethiopia. Patients, methods and baseline characteristics.

The ALERT MDT Field Evaluation Study (AMFES) is a long-term prospective study of 650 patients (594 new cases and 56 relapses after dapsone monotherapy), treated with fixed-duration multiple-drug therapy (MDT), as recommended by WHO. Follow-up has continued for up to 11 years from the start of treatment. This paper presents the methodology of the study and the baseline characteristics of the cohort, while accompanying papers examine the incidence of, and possible risk factors for, the various complications of leprosy, including relapse, reactions and nerve function impairment. The methods of diagnosis, classification and treatment with MDT are described; nerve function was assessed at every visit to the clinic using a standardized methodology, so that reactions and new impairment could be detected early and treated. Eighty-four per cent of new case had at least one thickened nerve, with the ulnar nerve most commonly involved. Seventy-seven per cent of cases completed treatment and only one adverse reaction to the MDT drugs was noted. Twenty-eight per cent of all patients were given steroids at one time or another, almost always for new nerve function impairment, and 3% of these developed significant complications of steroid treatment. Twenty-nine patients (5%) received hospital care, including 14 patients who underwent major surgery. Sixty-one per cent of the women over 19 years of age had at least one pregnancy, but pregnancies were much less common after leprosy was diagnosed.

Adolescent↗
PubMed2000

The pattern of leprosy-related neuropathy in the AMFES patients in Ethiopia: definitions, incidence, risk factors and outcome.

The ALERT MDT Field Evaluation Study (AMFES) began in 1988 and followed patients prospectively for up to 10 years after release from treatment (RFT). This paper presents the findings from this cohort with regard to neuropathy and nerve damage. Five hundred and ninety-four new cases of leprosy are included in the study, 300 multibacillary (MB) and 294 paucibacillary (PB) cases. Fifty-five percent of patients had some degree of impairment at diagnosis and a further 73 (12%) developed new nerve function impairment (NFI) after starting multiple drug therapy (MDT). The overall incidence rate for neuropathy was 39 episodes per 100 PYAR in the first year after diagnosis, gradually declining to 12 episodes per 100 PYAR in the sixth year. In those patients without impairment at diagnosis, the incidence rate of neuropathy was 25 episodes per 100 PYAR for MB cases and 11 per 100 PYAR for PB cases in the first year; in 33% of MB cases whose first episode of neuropathy occurred after diagnosis, that first episode took place after the first year, or after the normal period of treatment with MDT. Seventy-three patients with neuropathy developing after diagnosis are reported more fully: 34 (47%) had only one nerve involved and of these 25 (73%) had a single, acute episode of neuropathy. Nine (27%) had further episodes. Thirty-nine (53%) had more than one nerve involved and of these 16 (41%) had a single, acute episode, while 23 (59%) had further episodes. The terms 'chronic' and 'recurrent' neuropathy are defined and used to describe the pattern of neuropathy in those with repeated attacks. In patients with no impairment at the start of the study, treatment with steroids resulted in full recovery in 88% of nerves with acute neuropathy but only 51% of those with chronic or recurrent neuropathy. The median time to full recovery from acute neuropathy was approximately 6 months, but in a few cases recovery occurred gradually over 2-3 years. Severe neuropathy was less likely to be followed by a complete recovery than mild or moderate neuropathy. Forty-two percent of nerves with acute neuropathy that were not treated with steroids also fully recovered. In the group of patients who were thought to have old, permanent impairments at diagnosis, full recovery of nerve function occurred in 87/374 (23%) of the nerves involved. The overall outcome is illustrated by examining the average EHF score for groups of patients. Patients with no new neuropathy after diagnosis show a gradual improvement in their EHF score, while those with any episodes of neuropathy after diagnosis show a gradual deterioration after completion of MDT. Possible explanations for these findings are discussed. Risk factors for neuropathy, for chronic and recurrent neuropathy, and for a poor outcome 5 years after release from treatment, are examined. Impairment at diagnosis was the main risk factor for a poor outcome, accompanied by the occurrence of chronic/recurrent neuropathy or a reversal reaction.

Adult↗
PubMed2000

Reversal reactions in the skin lesions of AMFES patients: incidence and risk factors.

Reversal reactions affect the skin and/or nerves of leprosy patients. This paper looks at reversal reactions involving the skin in 594 new patients in central Ethiopia, followed for between 6 and 11 years after the start of treatment. The incidence of reversal reaction declines steadily after the start of treatment, but the first episode may occur as long as 5 years after diagnosis in both paucibacillary (PB) and multibacillary (MB) patients. Recurrent episodes occurred up to 6 years after diagnosis. PB patients were at greatest risk for reversal reaction in the first year after diagnosis and MB patients in the first 4 years. The highest incidence rate was 18 episodes per 100 person years in MB patients during the first year after diagnosis. The ratio of the incidence rates for the first 3 years in MB versus PB patients is 2.4 (95% CI 1.6-3.8). This study confirms that starting effective treatment and borderline classification are risk factors for reversal reactions. Pregnancy/delivery in the 6 months prior to diagnosis was a significant risk factor for presenting with a reversal reaction [relative risk (RR) 5.9 (95% CI 2.1-16.5)], but later pregnancies were not associated with an increased risk. Being female was a significant risk factor for the late appearance of the first episode of reversal reaction. Having a reversal reaction in the first year after diagnosis was a highly significant risk factor for the development of later reactions [RR in PB cases 11.9 (95% CI 3.4-41.7); in MB cases 6.4 (95% CI 3.8-10.6)]. Being HIV positive was a risk factor for developing recurrent reversal reactions, although only three out of 29 recurrent cases were HIV positive [RR 2.7 (95% CI 1.4-5.1)].

Adult↗
PubMed2000

ENL reactions in the multibacillary cases of the AMFES cohort in central Ethiopia: incidence and risk factors.

Erythema nodosum leprosum (ENL), or type 2 leprosy reactions are an important complication of multibacillary leprosy. The AMFES cohort includes 300 new multibacillary cases that have been followed for up to 10 years from the start of treatment, in central Ethiopia. Sixteen (5.3%) patients had ENL reactions. The incidence of ENL was maximal in the second and third years after the start of treatment, reaching 6.9 episodes per 100 person years at risk. Factors associated with being lepromatous [LL classification and a high bacillary index (BI)] gave an increased risk of developing ENL; in the univariate analysis, LL classification gave a relative risk of 3.6 (95% CI 1.3-10) and a BI of 6 gave a relative risk of 8.6 (95% CI 2.3-32) for the development of ENL. HIV co-infection was found to be a risk factor in this cohort, but as the numbers involved are small (only two HIV positive patients had ENL), this finding must be confirmed in larger studies. Ten of the 16 cases had recurrent episodes and five had at least five episodes occurring over a period of more than 2 years. The management and prognosis of ENL reactions are discussed.

Adult↗
PubMed2000

Relapses after fixed duration multiple drug therapy: the AMFES cohort.

Relapse rates after multiple-drug therapy (MDT) have been low, although there remains a concern about the possibility of late relapse in those with an initially high bacterial load. In all, 502 patients in the AMFES cohort completed fixed-duration MDT and are included in this report. There have been no confirmed relapses in the AMFES cohort, in a follow-up period of up to 8 years after completion of treatment, even in the 57 cases with an initial average bacillary index of > or = 4.0, 20 of whom have been followed for more than 5 years after ceasing MDT. Methods of diagnosing a relapse are discussed.

Adult↗
PubMed2000

The pattern of decline in bacillary index after 2 years of WHO recommended multiple drug therapy: the AMFES cohort.

With effective antibiotic treatment, the bacillary index (BI) in multibacillary leprosy patients declines over a number of years. This can be quantified as a rate of decline in log-units per year or as the time until smear negativity is reached. In the AMFES cohort 220 cases had data on the changes in their BI over time, while 170 cases are documented until smear negativity. The average BI at the start was 3.3 (SD 1.5; range 0.3-5.5) and the mean rate of decline was 0.85 units per year (median 0.7 units per year); in the first 2 years after diagnosis, the mean rate of decline was 1.15 units per year. The rate of decline was not related to any clinical features of the disease except delay in diagnosis: patients presenting for treatment early had a significantly faster rate of clearing the bacilli (adjusted relative risk 2.3; 95% CI 1.0-5.1). Fifty-eight percent of cases took longer than 3 years to reach smear negativity, but this time interval is largely determined by the initial BI and classification, making it a less useful indicator of bacterial clearance. More severe impairment at the start of treatment was associated with a faster return to smear negativity, for which no obvious explanation can be given. Reversal reactions, which occurred in 25% of the cases reviewed, are not associated with a more rapid clearance of bacilli.

Adult↗
PubMed2000

The effect of HIV status on the clinical picture of leprosy: a prospective study in Ethiopia.

No major interaction between HIV infection and leprosy has been documented. The ALERT MDT Field Evaluation Study (AMFES) has allowed the examination of possible interactions in a prospective manner, although the total number of HIV-positive individuals was not high at 22 (3.8%) of 581 patients tested. There was an excess number of deaths in the HIV-positive group: 27% compared with 5.7% in the HIV-negative group, although the causes of death were not recorded (relative risk 4.8; 95% CI 2.2-10.2). HIV-positive individuals had a higher risk of ENL reactions (relative risk 5.2; 95% CI 1.7-15.9). Reversal reactions and neuritis (both acute and chronic) were not significantly influenced by HIV status, although there was a possible increase in recurrent reversal reactions in HIV-positive cases (relative risk 2.2; 95% CI 0.98-4.7). There was no evidence to suggest an increased risk of developing leprosy or of developing multibacillary rather than paucibacillary disease. There was no association between HIV positivity and the development of impairment.

Adolescent↗
PubMed2000

Aims, options and outcomes in measuring maternal mortality in developing societies.

BACKGROUND: Effective methods for measuring maternal mortality in developing countries are important, particularly in assessing interventions aiming for safer motherhood. Here the performance of different approaches is compared in the same setting. METHODS: Estimates of maternal mortality in a rural Ethiopian community are reported, made by direct observation, a case-control approach, and the sisterhood method. RESULTS: Adjusted estimates of MMR using these methods ranged between 440 and 665 per 100,000 live births. CONCLUSIONS: The advantages and disadvantages of the different approaches are compared, both for operational feasibility and outcome.

Adolescent↗
PubMed1999

Incidence of malaria among children living near dams in northern Ethiopia: community based incidence survey.

OBJECTIVE: To assess the impact of construction of microdams on the incidence of malaria in nearby communities in terms of possibly increasing peak incidence and prolonging transmission. DESIGN: Four quarterly cycles of malaria incidence surveys, each taking 30 days, undertaken in eight at risk communities close to dams paired with eight control villages at similar altitudes but beyond flight range of mosquitoes. SETTING: Tigray region in northern Ethiopia at altitudes of 1800 to 2225 m. SUBJECTS: About 7000 children under 10 years living in villages within 3 km of microdams and in control villages 8-10 km distant. MAIN OUTCOME MEASURES: Incidence of malaria in both communities. RESULTS: Overall incidence of malaria for the villages close to dams was 14.0 episodes/1000 child months at risk compared with 1.9 in the control villages-a sevenfold ratio. Incidence was significantly higher in both communities at altitudes below 1900 m. CONCLUSIONS: There is a need for attention to be given to health issues in the implementation of ecological and environmental development programmes, specifically for appropriate malaria control measures to counteract the increased risks near these dams.

Adolescent↗
PubMed1998

Guidelines for anal cytology--to make cytological diagnosis and follow up much more reliable.

Anal intraepithelial neoplasia is a difficult diagnostic and management problem, particularly when it occurs in women with synchronous or metachronous genital intraepithelial neoplasia. Diagnosis and follow up by colposcopy is too specialized for widespread use, and although anal cytology has been used before it has been thought of as too inconsistent for practical application. This study standardized collection of specimens and investigated interobserver variation. The aim of the study was to determine whether observers could reliably distinguish high grade anal intraepithelial neoplasia from other conditions. Standardized collection of anal preparations was achieved in the host centre. A meeting of experienced cytopathologists was convened to agree guidelines for anal cytology. These guidelines were sent to the panel of six observers who were subsequently circulated with 30 cytopathological preparations in random order and asked to report them all. The results were collected and processed centrally. Four individuals were in complete agreement about those preparations which were inadequate for reporting, but two others had a lower threshold for rejecting preparations as inadequate. There was agreement between the observers in over 95% of cases in distinguishing high grade intraepithelial neoplasia from other cytological conditions. Kappa values range from 0.66 to 1.00. This study demonstrates that the provision of guidelines for the interpretation of anal cytopathological preparations can result in a high degree of interobserver agreement about the clinically important distinction between high grade anal intraepithelial neoplasia and other conditions. Anal cytology is a more useful technique for diagnosis and follow up of 'at risk' individuals than has previously been suggested, and should be utilized more widely in this group of patients.

Anal Canal↗