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Biomedical subjects

J D Clemens

Publications and source records attributed to J D Clemens.

At least 127 records · Page 7Linked to original sources
PubMed1987

Socioeconomic variables and rates of diarrhoeal disease in urban Bangladesh.

Sociodemographic factors including low maternal education, low economic status, inferior quality of housing, diminished access to water and sanitation facilities, and crowding in the household are associated with increased diarrhoea in the rural setting of many developing countries. To assess the relationship of these variables with diarrhoea rates in children in an urban setting we monitored the episodes of diarrhoea of children less than 6 years of age from 1921 families living in 51 clusters throughout Dhaka city, Bangladesh, for 3 1/2 months. Comparing incidence density ratios, we found that, of the factors listed above, only low family income and living in a one-room house were statistically associated with increased diarrhoea and that none of these variables was associated with a meaningfully increased risk of diarrhoea. We conclude that the risk factors for increased episodes of diarrhoea in the urban setting appear to be different from those of the rural setting.

Adolescent↗
PubMed1987

An educational intervention for altering water-sanitation behaviours to reduce childhood diarrhoea in urban Bangladesh: formulation, preparation and delivery of educational intervention.

The formulation, preparation and delivery of an educational intervention previously shown to alter hygienic practices and reduce rates of childhood diarrhea in 25 slum communities in Dhaka, Bangladesh is described in detail. Successful aspects of the program included involvement of community members in goal determination, involvement of community members and women as trainers, focusing conflict into positive actions and utilization of informal training techniques. The failures included inadequate transfer of technical aid to communities and insufficient involvement of volunteer-trainers in curriculum development. We suggest possible explanations for these successes and failures and suggest that these hypotheses should, if possible, be subjected to formal evaluation.

Audiovisual Aids↗
PubMed1987

B subunit-whole cell and whole cell-only oral vaccines against cholera: studies on reactogenicity and immunogenicity.

We conducted a randomized trial among persons in rural Bangladesh to evaluate the side effects and immunogenicity of orally administered B subunit-killed whole cell (BS-WC) and killed whole cell-only (WC) cholera vaccines and a killed Escherichia coli strain K12 placebo proposed for field testing. Three doses of BS-WC, WC, E. coli, or a control agent were given with antacid to 1,257 women (aged greater than 15 years) and children (aged to to 15 years). The four groups exhibited no statistically significant differences in occurrence of symptoms after each dose, and rises in titers of vibriocidal (VC) antibodies to Inaba and Ogawa were twofold higher for vaccinees than for controls (P less than .001). Half of the persons with fourfold or greater VC responses to WC responded after the first dose; many additional patients, particularly young children, responded after subsequent doses. In contrast, 89% of persons who responded to BS-WC with twofold or greater rises in titer of IgG antibodies to cholera toxin did so after the first dose. After the third dose, vaccinees exhibited a fivefold higher rise in titer than did controls (P less than .001); a dose-to-dose booster effect was most evident in young children.

Administration, Oral↗
PubMed1987

An educational intervention for altering water-sanitation behaviors to reduce childhood diarrhea in urban Bangladesh. I. Application of the case-control method for development of an intervention.

A case-control study was performed to develop an empirically based intervention for improving water-sanitation practices and rates of childhood diarrhea among families residing in urban Bangladesh. For three months fortnightly, histories of diarrhea were taken for all children under six years of age among 1,350 families to estimate age-specific rates of diarrhea in the population. A total of 247 randomly sampled families, termed sentinel families, were visited once during the study for prolonged observations of water-sanitation practices. Behaviors potentially affecting incidence of diarrhea were compared in a case group (n = 45), defined as sentinel families whose children had rates at least 1.7 times the rates expected for similarly aged children, and in a control group (n = 53), defined as sentinel families without any episodes of childhood diarrhea during the period of observation. Three practices differentiated the two groups: more control (82%) than case (53%) mothers who were observed to prepare food washed their hands before beginning the preparation (p less than 0.01); fewer control families (33%) than case families (80%) had ambulatory children who, when observed to defecate, did so in the family's living area (p less than 0.01); and fewer control (30%) than case (47%) families had children who were observed to place garbage or waste products in their mouth (p less than 0.10). Focus on these three empiric associations enabled the design of a community-specific educational intervention which is simple in construction and based upon naturally occurring, financially feasible, salutory practices.

Bangladesh↗
PubMed1987

An educational intervention for altering water-sanitation behaviors to reduce childhood diarrhea in urban Bangladesh. II. A randomized trial to assess the impact of the intervention on hygienic behaviors and rates of diarrhea.

An educational intervention was designed to improve three water-sanitation behaviors empirically shown to be associated with high rates of childhood diarrhea in Dhaka, Bangladesh: lack of handwashing before preparing food, open defecation by children in the family compound, and inattention to proper disposal of garbage and feces, increasing the opportunity for young children to place waste products in their mouth. Fifty-one communities, each comprising 38 families, were randomized either to receive (n = 25) or not to receive (n = 26) the intervention. During the six months after the intervention, the rate of diarrhea (per 100 person-weeks) in children under six years of age was 4.3 in the intervention communities and 5.8 in the control communities (26% protective efficacy; p less than 0.0001). A corresponding improvement in handwashing practices before preparing food was noted, although no improvement was observed for defecation and waste disposal practices. These data suggest that educational interventions for water-sanitation practices can have an important beneficial effect upon childhood diarrhea in developing countries, particularly when the interventions are designed in a simple way to promote naturally occurring salutory behaviors that are empirically associated with lower rates of childhood diarrhea.

Bangladesh↗
PubMed1987

An urban nutrition education and rehabilitation centre: a description of the programme and change in nutritional status of children who were enrolled.

We report on a community-based day care nutrition rehabilitation and education centre which was established by the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) in a slum in Dhaka, Bangladesh. Between March-December, 1985 approximately 10 children aged 1 to 5 years with a percent weight for height (% wt/ht) of 60 to 85 were enrolled in each of 9 sessions which were 3 to 5 weeks long. The children were fed 3 meals and 2 snacks daily made from locally available inexpensive foods. A nutrition education programme, developed with input from several feeding centres in Dhaka, included daily lessons, participatory cooking and personal hygiene sessions. Of the 85 children entering the programme, 82 (95%) completed 3 or more weeks. Relative to baseline, a median increase of 8.7% wt/ht was observed at 5 weeks (p less than 0.001), with the greatest improvement occurring in those children presenting with the lowest weights. Median increases of 7.2 and 7.4% wt/ht were noted 6 and 10 months after admission, respectively. Gender and minor illness did not have a significant impact on change in nutritional status. Poor performance of mothers in assigned chores was associated with inferior improvement in nutritional status 5 weeks but not 6 months post-admission. These results suggest that the intervention implemented by the centre may have been effective in improving nutritional status and that more rigorous evaluation of participants in relation to suitably matched concurrent controls should be performed.

Bangladesh↗
PubMed1987

Twenty-four-hour recall, knowledge-attitude-practice questionnaires, and direct observations of sanitary practices: a comparative study.

Although responses to 24-hour recall and knowledge-attitude-practice questionnaires are commonly used in water-sanitation studies as surrogates for direct observation of behaviour, the validity of this approach is questionable. We therefore compared questionnaire data with those obtained by direct observation of practices related to water storage, handwashing, and defecation among 247 families in urban Dhaka, Bangladesh. Analysis of the results indicates that accord between the replies to the questionnaires and the data collected by direct observation was poor and that the responses to the two questionnaires were often contradictory. Significant disagreements between the results of questionnaires and observations arose usually because desirable practices were over-reported by the respondents. The results of the study suggest that in urban Bangladesh 24-hour recall and knowledge-attitude-practice questionnaires should not be used as proxies for direct observation of hygiene practices.

Bangladesh↗
PubMed1986

Field trial of oral cholera vaccines in Bangladesh.

The protective efficacy of oral B subunit killed whole-cell (BS-WC) and killed whole-cell (WC) cholera vaccines was assessed in 63 498 Bangladeshi children aged 2-15 years and women aged over 15 years. Each received three doses of BS-WC, WC, or placebo in a randomised, double-blinded fashion. Surveillance for cases seeking medical care up to six months after the third dose revealed 26 cases of confirmed cholera in the placebo group, 4 cases in the BS-WC group (protective efficacy 85%; p less than 0.0001), and 11 cases in the WC group (protective efficacy 58%; p less than 0.01). For each vaccine protective efficacy was consistent in different age-groups (2-10 years versus greater than 10 years) and for different severities of cholera.

Administration, Oral↗
PubMed1986

Risk factors for developing mild nutritional blindness in urban Bangladesh.

Mild vitamin A deficiency may be associated with increased morbidity and mortality among children in developing countries. A community-based case-control study was performed to determine risk factors for mild ophthalmologic manifestations of vitamin A deficiency in urban Bangladeshi children. Cases were identified in children less than 14 years of age with night blindness with or without other signs of mild xerophthalmia detected in a house-to-house survey. Controls were randomly selected neighbors who lacked subjective and objective ophthalmologic evidence of vitamin A deficiency. Demographic characteristics that were independently associated with vitamin A deficiency in a logistic model included male gender, greater age (mean, 6.1 years in children with cases and 2.8 years in controls), and a greater number of children living with the family. After controlling for these demographic characteristics, poor intake of locally available vitamin A-rich foods, cessation of breast-feeding, and a recent history of protracted diarrhea remained associated with vitamin A deficiency. Maternal ignorance of prevention and control of vitamin A deficiency was also associated with increased risk. The results support programs that educate mothers to breast-feed and to provide appropriate food supplements and suggest that clinicians caring for children with chronic diarrhea should initiate vitamin A supplementation.

Adolescent↗
PubMed1986

A new clinical-anatomic staging system for evaluating prognosis and treatment of prostatic cancer.

Because the existing systems of staging for prostatic cancer depend exclusively on the extent of anatomic spread, the stages do not demarcate distinctive patterns of survival, particularly in patients with extremely good or poor prognoses. In this research, we demonstrate that the evaluation of prognosis and therapy can be improved if anatomic staging is augmented by various features of the patients' clinical severity. In 280 patients with prostatic cancer, we first created rating scales for severity of three distinct clinical variables: symptoms referable to cancer; host factors unrelated to cancer; and overall level of function. In univariate analysis each of these clinical variables substantially affected 5-year survival for patients with similar anatomic stages, but in multivariate analysis, only the first two (symptoms and host factors) remained impressive. Retaining the anatomic stages and adding the two most important clinical variables, we then created a composite new staging system, containing four clinical-anatomic (C-A) categories. The new C-A categories were statistically more distinctive than conventional anatomic stages, and demarcated patients with more extreme high (91%) and low (8%) 5-year survival rates. In addition to the increased prognostic precision, the new C-A staging system demonstrated an important distinction in treatment. Although radical radiotherapy seemed superior to palliative therapy within conventional anatomic stages, the survival differences disappeared within the C-A stages.

Adult↗
PubMed1986

Soiled saris: a vector of disease transmission?

We examined the relationship between uses of the sari that are potential health hazards and episodes of diarrhoea in children younger than 6 years in 247 families living in 51 slums in Dhaka, Bangladesh. These misuses appeared to be common (median of three per observation period) and were largely unrecognized by the women as possible sources of disease transmission. There appeared to be a positive correlation between the number of misuses of the sari and episodes of childhood diarrhoea.

Animals↗
PubMed1986

Breast feeding as a determinant of severity in shigellosis. Evidence for protection throughout the first three years of life in Bangladeshi children.

Little is known about the effect of breast feeding upon the severity of illness due to specific diarrheal pathogens. Using a systematically sampled and evaluated population of children aged less than 3 years, who attended a diarrheal disease hospital in Bangladesh, the authors performed a case-control study that assessed whether breast feeding reduces the severity of illness in shigellosis. From 540 children presenting with shigellosis between 1980-1982, they created a group of cases (n = 53) with severe illness and controls (n = 487) with non-severe illness. Overall, the odds ratio relating breast feeding to the severity of shigellosis (0.49, p = 0.01) suggested a substantial mitigating effect of breast feeding upon clinical severity. The high degree of protection against severe shigellosis was evident for breast-fed children up to 35 months of age, as well as for children at high risk for death because of severe malnutrition or measles. Because shigellosis continues to account for substantial morbidity and mortality in children in developing countries, the results support prolonged breast feeding in these settings.

Bangladesh↗
PubMed1984

Changing spectrum of infective endocarditis in children. Analysis of 26 cases, 1970-1979.

The decade of the 1970s was marked by an increased survival of children with complex heart lesions, use of prosthetic material in open heart surgery, and placement of indwelling central catheters in critically ill patients. We analyzed all 26 cases of children with infective endocarditis (IE) seen at Yale University, New Haven, Conn, from 1970 through 1979 to determine whether these and other factors resulted in a change in pediatric IE. A larger proportion of cases arose postoperatively as compared with previous series. Among the postsurgical and catheterization-related cases, the most common infecting agents were streptococci, not the expected staphylococci. Although the number of cases was small, IE associated with prosthetic material had a favorable prognosis; all survivors of IE with prosthetic material were cured by medical regimens alone. The IE cases in children with previously normal hearts were associated with indwelling central catheters.

Anti-Bacterial Agents↗
PubMed1984

A quantitative assessment of pre-dental antibiotic prophylaxis for patients with mitral-valve prolapse.

Because antibiotic prophylaxis for dental procedures in patients with mitral-valve prolapse (MVP) has been controversial, we performed a decision analysis to assess the costs and effects of the oral and parenteral penicillin regimens currently recommended for patients at high risk for bacterial endocarditis. The analysis suggests that there is a very small risk of post-dental endocarditis in MVP (4.1 cases per 10(6) procedures) which is outweighed by a greater risk of fatal reactions to parenteral penicillin (15 deaths per 10(6) courses). Parenteral penicillin prophylaxis therefore causes a net loss of life. For oral penicillin the risk of a fatal reaction is lower (0.9 deaths per 10(6) courses). However, oral penicillin prophylaxis appears to spare life only in older adults with MVP and at an extremely high cost: Over +1 million must be spent to spare one year of life. Personal preferences may still make antibiotic prophylaxis desirable for individual MVP patients. However, from a societal perspective, routine predental antibiotic prophylaxis for MVP is a very expensive preventive strategy.

Administration, Oral↗
PubMed1984

BCG prophylaxis against cancer: methodological evaluation of a continuing controversy.

A possible protective effect of tuberculosis against cancer, together with the known immune-stimulating properties of BCG, have motivated 14 investigations of BCG prophylaxis against cancer. The results have been conflicting: 3 studies found high levels of protection, 8 found no effect, and 3 suggested that BCG may actually raise the risk of cancer. To assess whether the inconsistent results could have a methodological basis, we analyzed each study according to several basic criteria necessary for scientific validity in cause-effect research. The analyses showed two major problems: (1) None of the studies used safeguards against detection bias by ensuring that the diagnosis of cancer in vaccinees and non-vaccinees was made with equal follow-up and surveillance procedures, and in an accurate and unbiased fashion; (2) Studies alleging that BCG is carcinogenic were weakened by the inappropriate use of cancer mortality data, by the analysis of multiple BCG-cancer associations without appropriate statistical adjustment, and by post hoc creation of new cancer risk categories after inspection of the data. Since these methodologic inadequacies preclude any firm conclusions about the role of BCG in preventing cancer, a resolution of the controversy will require new research, designed and conducted with greater attention to methodologic principles necessary to ensure scientific validity.

BCG Vaccine↗
PubMed1984

A controlled evaluation of the protective efficacy of pneumococcal vaccine for patients at high risk of serious pneumococcal infections.

The protective efficacy of pneumococcal vaccine against systemic pneumococcal infections in adults with the current indications for the vaccine was evaluated in a case-control study. Six (7%) of the 90 cases and 16 (18%) of the matched controls had received pneumococcal vaccine for an odds ratio of 0.33 (p less than 0.05). The vaccine's protective efficacy was 67%, which remained virtually unchanged after adjusting for potential confounding variables. The vaccine's efficacy was 77% for patients at moderately increased risk of pneumococcal infections, but 0% for patients who were severely immunocompromised. The vaccine's protective efficacy was 70% (p less than 0.05) for all patients 55 years or older after controlling for indications for the vaccine in addition to age. Pneumococcal vaccine confers substantial protection against systemic pneumococcal infections on the elderly and patients with illnesses associated with a moderately increased risk of pneumococcal infections.

Adolescent↗
PubMed1984

Longitudinal methods for evaluating therapy.

Longitudinal studies of therapy are unparalleled in their ability to ensure scientifically cogent results by clearly separating cause (therapy) from effect (therapeutic outcome), by allowing incorporation of duration of follow-up into the assessment of comparative outcomes, and by permitting the use of safeguards against non-concurrent therapies, unequal prognostic susceptibilities, unequal therapeutic performance, and unequal detection of outcomes. The price of these advantages includes the reduced ability of longitudinal studies to evaluate therapies whose outcomes occur rarely or with long latencies, as well as the specific logistic, ethical, and design problems that limit the ability of clinical trials to answer many of the therapeutic questions which are important to clinical practice. The implications of these limitations are that longitudinal evaluations may not be suitable for addressing many therapeutic issues--particularly those involving preventive therapies--and that even when longitudinal studies are suitable, randomized trials may not be logistically feasible or ethically permissible to answer every clinically important question. One of the important challenges for research in this area is to develop alternative methods for assessing therapeutic effectiveness.

Clinical Trials as Topic↗