Biomedical subjects

J M Tielsch

Publications and source records attributed to J M Tielsch.

At least 55 records · Page 3Linked to original sources

PubMed1998

Evaluation of screening schemes for eye disease in a primary care setting.

BACKGROUND AND PURPOSE: Screening in a primary care setting could be an effective method for detection of eye disease. This study was designed to evaluate a questionnaire and a battery of tests for their performance in eye disease screening at a primary care clinic. METHODS: 405 patients aged 40 years or older were interviewed and received a comprehensive eye examination including visual acuity and visual field testing, tonometry, slit-lamp examination, dilated fundus examination and photography. Sensitivity and specificity for the identification of eye disease were calculated for each test and various combinations of tests. RESULTS: A questionnaire-based algorithm for detection of overall eye disease was sufficiently sensitive (90%) but less specific (44%) than an ideal screening test. Distance visual acuity with presenting correction of < or = 20/40 had a sensitivity of 61% and specificity of 72%. A dilated fundus examination had a sensitivity of 79% and specificity of 82%. In screening for glaucoma, tonometry was ineffective (sensitivity = 27% and specificity = 96%), while visual field testing by suprathreshold screening had a sensitivity of 70% and specificity of 67%. Among a variety of combinations, a two-stage strategy with the questionnaire as a first-stage and visual acuity and ophthalmoscopy as second-stage tests provided the best balance of sensitivity (83%) and specificity (76%). CONCLUSION: Among currently available ophthalmic tests, an eye examination including a thorough fundus examination is critical in detection of eye disease. A five-item questionnaire may be useful to identify patients at high risk in primary care practice. More effective tests are needed to improve performance of eye disease screening.

Adult↗

PubMed1998

Effects of the Zanzibar school-based deworming program on iron status of children.

We evaluated the effects of the Zanzibar school-based deworming program on the iron status of primary school children. Parasitologic and nutritional assessments were carried out at baseline, 6 mo, and 12 mo in 4 nonprogram schools (n = 1002), 4 schools in which students received twice-yearly deworming (n = 952), and 4 schools in which students received thrice-yearly deworming (n = 970) with 500 mg generic mebendazole. Schools were randomly selected for evaluation and allocated to program groups. Relative to no treatment, thrice-yearly deworming caused significant decreases in protoporphyrin concentrations and both deworming regimens caused marginally significant increases in serum ferritin concentrations. The average annual changes in protoporphyrin concentrations were -5.9 and -23.5 micromol/mol heme in the control and thrice-yearly deworming groups, respectively (P < 0.001). The average changes in ferritin concentration were 2.8 and 4.5 microg/L, respectively (P = 0.07). Deworming had no effect on annual hemoglobin change or prevalence of anemia. However, the relative risk of severe anemia (hemoglobin < 70 g/L) was 0.77 (95% confidence limits: 0.39, 1.51) in the twice-yearly deworming group and 0.45 (0.19, 1.08) in the thrice-yearly deworming group. The effects on prevalence of high protoporphyrin values and incidence of moderate-to-severe anemia (hemoglobin < 90 g/L) were significantly greater in children with > 2000 hookworm eggs/g feces at baseline. We estimate that this deworming program prevented 1260 cases of moderate-to-severe anemia and 276 cases of severe anemia in a population of 30,000 schoolchildren in 1 y. Where hookworm is heavily endemic, deworming programs can improve iron status and prevent moderate and severe anemia, but deworming may be needed at least twice yearly.

Ancylostomiasis↗

PubMed1998

Epidemiological evidence for a differential effect of hookworm species, Ancylostoma duodenale or Necator americanus, on iron status of children.

BACKGROUND: The hookworms, Ancylostoma duodenale and Necator americanus, cause significant gastrointestinal blood loss. In clinical studies, greater blood losses have been reported with A. duodenale. However, there has been no evidence that endemic A. duodenale infection has greater impact than N. americanus infection on the iron status of populations. METHODS: In a sample of 525 school children in Pemba Island, Tanzania, we compared the degree of anaemia and iron deficiency associated with the two hookworm species at the individual and community (i.e. school) levels. Multiple regression was used to control for infection intensities and other child characteristics. RESULTS: In the 492 children with hookworm positive faecal cultures, haemoglobin and ferritin concentrations decreased with increasing proportions of A. duodenale. Among children with only N. americanus larvae, the prevalence of anaemia was 60.5 % and the prevalence of ferritin <12 microg/l was 33.1%, while in children with > or =50% A. duodenale larvae, the respective prevalences were 80.6% and 58.9%. When children were grouped by the prevalence of A. duodenale at the school level, children from high prevalence (> or =20%) schools had significantly worse iron deficiency and anaemia than children from low prevalence schools. CONCLUSIONS: The species of hookworm being transmitted in a community influences the burden of iron deficiency anaemia in the community, and should be considered in prioritizing and planning programmes for hookworm and anaemia control.

Ancylostomiasis↗

PubMed1998

Statewide regionalization of pancreaticoduodenectomy and its effect on in-hospital mortality.

OBJECTIVE: This study examined a statewide trend in Maryland toward regionalization of pancreaticoduodenectomy over a 12-year period and its effect on statewide in-hospital mortality rates for this procedure. SUMMARY BACKGROUND DATA: Previous studies have demonstrated that the best outcomes are achieved in centers performing large numbers of pancreaticoduodenectomies, which suggests that regionalization could lower the overall in-hospital mortality rate for this procedure. METHODS: Maryland state hospital discharge data were used to select records of patients undergoing a pancreaticoduodenectomy between 1984 and 1995. Hospitals were classified into high-volume and low-volume provider groups. Trends in surgical volume and mortality rates were examined by provider group and for the entire state. Regression analyses were used to examine whether hospital share of pancreaticoduodenectomies was a significant predictor of the in-hospital mortality rate, adjusting for study year and patient characteristics. The portion of the decline in the statewide in-hospital mortality rate for this procedure attributable to the high-volume provider's increasing share was determined. RESULTS: A total of 795 pancreaticoduodenectomies were performed in Maryland at 43 hospitals from 1984 to 1995 (Maryland residents only). During this period, one institution increased its yearly share of pancreaticoduodenectomies from 20.7% to 58.5%, and the statewide in-hospital mortality rate for the procedure decreased from 17.2% to 4.9%. After adjustment for patient characteristics and study year, hospital share remained a significant predictor of mortality. An estimated 61% of the decline in the statewide in-hospital mortality rate for the procedure was attributable to the increase in share of discharges at the high-volume provider. CONCLUSIONS: A trend toward regionalization of pancreaticoduodenectomy over a 12-year period in Maryland was associated with a significant decrease in the statewide in-hospital mortality rate for this procedure, demonstrating the effectiveness of regionalization for high-risk surgery.

Aged↗

PubMed1998

The importance of surgeon experience for clinical and economic outcomes from thyroidectomy.

OBJECTIVE: To determine whether individual surgeon experience is associated with improved short-term clinical and economic outcomes for patients with benign and malignant thyroid disease who underwent thyroid procedures in Maryland between 1991 and 1996. SUMMARY BACKGROUND DATA: There is a prevailing belief that surgeon experience affects patient outcomes in endocrine surgery, but there is a paucity of objective evidence outside of clinical series published by experienced surgeons that supports this view. METHODS: A cross-sectional analysis of all patients who underwent thyroidectomy in Maryland between 1991 and 1996 was conducted using a computerized statewide hospital discharge data base. Surgeons were categorized by volume of thyroidectomies over the 6-year study period: A (1 to 9 cases), B (10 to 29 cases), C (30 to 100 cases), and D (>100 cases). Multivariate regression was used to assess the relation between surgeon caseload and in-hospital complications, length of stay, and total hospital charges, adjusting for case mix and hospital volume. RESULTS: The highest-volume surgeons (group D) performed the greatest proportion of total thyroidectomies among the 5860 discharges, and they were more likely to operate on patients with cancer. After adjusting for case mix and hospital volume, highest-volume surgeons had the shortest length of stay (1.4 days vs. 1.7 days for groups B and C and 1.9 days for group A) and the lowest complication rate (5.1 % vs. 6.1% for groups B and C and 8.6% for group A). Length of stay and complications were more determined by surgeon experience than hospital volume, which had no consistent association with outcomes. CONCLUSIONS: Individual surgeon experience is significantly associated with complication rates and length of stay for thyroidectomy.

Clinical Competence↗

PubMed1998

Importance of hospital volume in the overall management of pancreatic cancer.

OBJECTIVE: To determine whether hospital volume is associated with clinical and economic outcomes for patients with pancreatic cancer who underwent pancreatic resection, palliative bypass, or endoscopic or percutaneous stent procedures in Maryland between 1990 and 1995. SUMMARY BACKGROUND DATA: Previous studies have demonstrated that outcomes for patients undergoing a Whipple procedure improve with higher surgical volume, but only 20% to 35% of patients with pancreatic cancer qualify for curative resection. Most patients undergo palliative procedures instead with a surgical bypass or biliary stent. METHODS: Analysis of hospital discharge data from all nonfederal acute care hospitals in Maryland identified all patients with pancreatic cancer who underwent a pancreatic resection, palliative bypass, or stent procedure between 1990 and 1995. Hospitals (n = 48) were categorized as high-, medium-, and low-volume providers according to their average annual volume of these procedures. Multivariate regression was used to examine the association between hospital volume and in-hospital mortality rate, length of stay, and hospital charges, after adjusting for differences in case mix and surgeon volume. RESULTS: Increased hospital volume is associated with markedly decreased in-hospital mortality rates and a decreased or similar length of stay for all three types of procedures and with decreased or similar hospital charges for resections and stents. After adjustment for case mix differences, the relative risk (RR) of in-hospital death after pancreatic resection was 19.3 and 8 at the low- and medium-volume hospitals, respectively, versus the high-volume hospital; after bypasses, the RR of death was 2.7 and 1.9, respectively; and after stents, the RR was 4.3 and 4.8, respectively. CONCLUSIONS: Patients with pancreatic cancer who are to be treated with curative or palliative procedures appear to benefit from referral to a high-volume provider.

Aged↗

PubMed1997

Prevalence of dry eye among the elderly.

PURPOSE: To study the demographics and estimate the prevalence of dry eye among elderly Americans. METHODS: A population-based prevalence study was performed in 2,520 residents of Salisbury, Maryland, aged 65 years and older as of September 1993. The population was derived from the Health Care Financing Administration Medicare database. After completing a standardized questionnaire pertaining to dry eye symptoms, 2,420 subjects underwent Schirmer and rose bengal tests and anatomic assessment of the meibomian glands. RESULTS: In this population, 14.6% (363/2,482) were symptomatic, defined as reporting one or more dry eye symptoms often or all the time; 2.2% (53/2,448) were symptomatic and had a low Schirmer test result (< or = 5 mm), and 2% (48/2,432) were symptomatic and had a high rose bengal test score (> or = 5). Furthermore, 3.5% (84/2,425) were symptomatic and had either a low Schirmer score or a high rose bengal score, and 0.7% (17/2,420) were symptomatic and had both a low Schirmer score and a high rose bengal score. No association of symptoms or signs was seen with age, sex, or race. Although anatomic features of meibomianitis were associated with the presence of symptoms (P = .01), 76% (67/88) of the individuals with these anatomic features were asymptomatic; 10.5% (260/2,480) reported that they currently use artificial tears or lubricants. CONCLUSIONS: Symptoms and signs of dry eye are common among the elderly but were not associated with age, race, or sex in this population-based sample of elderly Americans. Extrapolating to the United States population aged 65 to 84 years, the study yields an estimate of 4.3 million who experience symptoms of ocular irritation often or all the time.

Aged↗

PubMed1997

Biometry and primary angle-closure glaucoma among Chinese, white, and black populations.

PURPOSE: Primary angle-closure glaucoma (PACG) is more prevalent among Chinese than whites. The authors tested the hypothesis that Chinese have shallower anterior chambers than do whites, a factor that may be related to PACG prevalence. METHODS: The authors compared anterior chamber depth, axial length, radius of corneal curvature, and refractive error among 531 Chinese, 170 whites, and 188 blacks older than 40 years of age using the same model of instruments and identical technique. RESULTS: Mean anterior chamber depth and axial length did not differ significantly for the three groups. Whites had a significantly higher prevalence of hyperopia > 2 diopters than did Chinese. Radius of corneal curvature was significantly smaller among Chinese than whites or blacks. CONCLUSIONS: These results suggest that Chinese do not differ on a population basis from other ethnic groups in many of the biometric risk factors known to be of importance for PACG. It will be necessary to identify other ocular biometric parameters to explain the excess burden of PACG among Chinese, which may improve the effectiveness of screening for this disease in all populations.

Adult↗

PubMed1997

Relation between signs and symptoms of dry eye in the elderly. A population-based perspective.

PURPOSE: To examine the distribution and association of dry eye symptoms, Schirmer test results, and rose bengal scores in a population-based sample of elderly Americans. DESIGN: Population-based prevalence survey. PARTICIPANTS: Involved were 2240 noninstitutionalized residents of Salisbury, Maryland, aged 65 years and older as of September 1993, and identified by the Health Care Financing Administration Medicare database. MAIN OUTCOME MEASURES: A standardized dry eye symptom questionnaire, rose bengal scoring of ocular surface staining, and Schirmer tests. RESULTS: Fourteen percent of participants reported one or more symptoms to be present often or all the time. The mean Schirmer score in the lower testing eye was 12.4 and 42% had a rose bengal score of 1 or greater. No significant differences by age, gender, or race were seen for symptoms, Schirmer, or rose bengal testing. No association was seen between lower Schirmer scores and presence of more frequent symptoms. Higher rose bengal scores were weakly associated with symptoms. The Schirmer and rose bengal test results, both individually and in combination, were insensitive in identifying individuals who had symptoms. CONCLUSIONS: Although symptoms of ocular irritation are common among the elderly, these population-based data indicate that there is minimal overlap between individuals identified by questionnaire, Schirmer tests, and rose bengal scoring.

Aged↗

PubMed1997

Epidemiology of iron deficiency anemia in Zanzibari schoolchildren: the importance of hookworms.

Anemia is estimated to affect one-half of school-age children in developing countries. The school years are an opportune time to intervene, and interventions must be based on sound epidemiologic understanding of the problem in this age group. We report on the distribution of iron deficiency and anemia across age, sex, anthropometric indexes, and parasitic infections in a representative sample of 3595 schoolchildren from Pemba Island, Zanzibar. Iron status was assessed by hemoglobin, erythrocyte protoporphyrin (EP), and serum ferritin concentrations from a venous blood sample. Overall, 62.3% of children were anemic (hemoglobin < 110 g/L), and 82.7% of anemia was associated with iron deficiency. The overall prevalence of iron-deficient erythropoiesis (EP > 90 mumol/mol heme) was 48.5%, and the prevalence of exhausted iron stores (serum ferritin < 12 micrograms/L) was 41.3%. In bivariate analyses, iron status was slightly better in girls than in boys, and was better in children aged 7-11 y than in those older or younger. Hemoglobin but not EP or serum ferritin concentrations were lower in stunted children. Infection with malaria, Trichuris trichiura, Ascaris lumbricoides, and hookworms were all associated with worse iron status; the association with hookworms was strongest by far. In multivariate analyses, hookworm infection intensity was the strongest explanatory variable for hemoglobin, EP, and serum ferritin. Sex, malarial parasitemia, A. lumbricoides infection, and stunting were also retained in the multivariate model for hemoglobin. Twenty-five percent of all anemia, 35% of iron deficiency anemia, and 73% of severe anemia were attributable to hookworm infection; < 10% of anemia was attributable to A. lumbricoides, malaria infection, or stunting. We conclude that anthelminthic therapy is an essential component of anemia control in schoolchildren in whom hookworms are endemic, and should be complemented with school-based iron supplementation.

Adolescent↗

PubMed1997

School-based deworming program yields small improvement in growth of Zanzibari school children after one year.

Efficacy trials of antihelminthic therapies conducted in Africa have reported improvements in children's growth, but nutritional evaluations of large-scale deworming programs are lacking. We evaluated the first-year effect on growth of a school-based deworming program in Zanzibar, where growth retardation occurs in school children. Children in four primary schools were given thrice-yearly mebendazole (500 mg) and compared with children in four schools that received twice-yearly mebendazole and children in four non-program schools. Evaluation schools were randomly selected and allocated to control, twice-yearly or thrice-yearly deworming. Approximately 1000 children in each program group completed the 1-y follow-up. Children <10 y old gained 0.27 kg more weight (P < 0.05) and 0.13 cm more height (P = 0.20) in the twice-yearly group, and 0. 20 kg more weight (P = 0.07) and 0.30 cm more height (P < 0.01) in the thrice-yearly group, compared with the control group. Children <10 y old with higher heights-for-age at baseline had higher weight and height gains in response to deworming. In children >/=10 y old, overall program effects on height or weight gains were not significant. But in this age range, younger boys had significant improvements in height gain with thrice-yearly deworming, and children with higher heights-for-age had greater improvements in weight gain with deworming. We conclude that the deworming program improved the growth of school children, especially children who were younger and less stunted, but the improvements were small. More effective antihelminthic regimens or additional dietary or disease control interventions may be needed to substantially improve the growth of school children in areas such as Zanzibar.

Animals↗

PubMed1997

Serum ferritin, erythrocyte protoporphyrin and hemoglobin are valid indicators of iron status of school children in a malaria-holoendemic population.

In many African populations, the prevalences of both iron deficiency and malarial infection exceed 50%. The control of iron deficiency anemia is of urgent public health importance, but assessment of iron status in these contexts has been controversial because of the effects of malarial disease on common iron status indicators. We assessed iron status in 3605 school children in Zanzibar by measuring hemoglobin, erythrocyte protoporphyrin (EP) and serum ferritin concentrations. Malaria parasitemia was quantified by counting against leukocytes. Iron deficiency was highly prevalent: 62.4% of hemoglobin concentrations were <110 g/L, 59.7% of EP values were >80 micromol/mol heme, and 41.5% of ferritin concentrations were <12 microg/L. Prevalence of Plasmodium falciparum parasitemia was 60.6%, but <1% of children had densities above 5000 parasites/microL blood. Neither hemoglobin nor EP concentration was associated with malaria parasite density, but prevalence of abnormal values increased by < or = 25% with parasite density. Erythrocyte protoporphyrin and hemoglobin were strongly inversely related regardless of parasite density. The relationship of EP to hemoglobin was slightly attenuated when parasite density exceeded 1000 parasites/microL blood. Ferritin rose by 1.5 microg/L per 1000 parasites/microL for parasite densities >1000 parasites/microL, but the relationship of ferritin to hemoglobin or EP was strong even when parasite densities exceeded this cutoff. The population prevalences of iron deficiency were not significantly biased by malarial infection. In this population of school children, iron status assessment using these indicators was not seriously influenced by malarial infection. We hypothesize that these indicators perform reliably in populations in which malarial infection is infrequently associated with disease; namely older children and adults in holoendemic environments.

Adolescent↗

PubMed1997

Linear growth retardation in Zanzibari school children.

This paper describes the longitudinal changes in height and weight of children in school grades 1-3 on Pemba Island, Zanzibar, a poor rural population in which parasitic infections and anemia are highly prevalent. Heights and weights of children were measured at base line, and 6 and 12 mo later, and were compared with U.S. reference data. At base line, the prevalence of height-for-age Z-score < -2 rose from 14% in 7-y-old children to 83% in 13-y-old children. Prevalence of weight-for-age Z-score < -2 in children < 10 y was approximately 10% or less. Median 6-mo height increments for Pembian boys were around the 5th percentile at age 8 and around the 10th percentile from age 9 to 13 y. Height increments for girls improved from below the 25th percentile to above the median in this age range. Based on the longitudinal yearly gains observed, boys accumulate a height deficit of 11.9 cm and girls 8.5 cm, relative to the reference population. In multivariate analyses, a small part of the variability in growth increments was explained by ascariasis and anemia (for weight gain) and schistosomiasis (for height gain). A review of other growth data from rural African Bantu populations provides supporting evidence that stunting occurs in older as well as younger children. It has been controversial whether school-based health and nutrition interventions could induce catch-up growth in already stunted children. Our results suggest that appropriate interventions might actually prevent stunting in late childhood.

Adolescent↗

PubMed1997

Racial variations in treatment for glaucoma and cataract among Medicare recipients.

PURPOSE: To identify the location of barriers to treatment for glaucoma and cataract among African-American Medicare beneficiaries. METHODS: We examined the receipt of eye care in general and care for glaucoma and cataract in particular among black and white Medicare beneficiaries using 1991 Medicare physician claims data. Racial differences in treatment for glaucoma and cataract were examined both for the Medicare population as a whole and for identified eye care users. The results were compared to the expected value of black-white difference based on population prevalence data for each specific condition. RESULTS: Thirty percent of black beneficiaries and 45% of white Medicare beneficiaries used eye care services in 1991. After adjusting for the expected difference in prevalence, black beneficiaries were half as likely to be surgically treated for glaucoma compared to white beneficiaries, and 80% as likely for cataract. When the analysis was restricted to those using eye care services, blacks continued to have lower than expected rates of treatment for glaucoma (observed RR = 3.2, 95% confidence interval = 3.1-3.4 vs an expected RR of 4.3, 95% confidence interval = 3.5-5.4), but a higher rate of treatment for cataract (RR = 1.2, 95% confidence interval = 1.2-1.3). Among those with physician-diagnosed glaucoma and cataract, blacks were more likely to undergo surgical treatment for these conditions than whites (RR = 1.5 for glaucoma, 95% confidence interval = 1.4-1.5; RR = 1.2 for cataract, 95% confidence interval = 1.2-1.3). CONCLUSION: Barriers to treatment for glaucoma and cataract among black Medicare beneficiaries involve primarily limitations in access to the eye care system. The undertreatment for glaucoma among black beneficiaries was reduced, but not eliminated, after removing the effect of unequal access to the eye care system.

Black or African American↗

PubMed1997

Effects of randomizing second eyes in a trial to evaluate preoperative medical testing for cataract surgery.

The statistical and practical implications of including second eye surgeries were examined in a clinical trial designed to evaluate the impact of routine preoperative testing prior to cataract surgery on major medical events occurring within seven days following surgery. In order to detect a 0.8% difference in the rates of rare major medical events between the tested and untested groups, 20,000 surgeries must be randomized. About 30% of cataract operations were estimated to be done on second eyes of patients already included in the cohort. Different options for dealing with second eye surgeries were: (1) exclusion of all second eye surgeries, (2) inclusion of second eye surgeries only if the first eye is not enrolled, (3) inclusion of first and second eyes but randomization of patients rather than eyes, and (4) inclusion of first and second eyes but randomization of surgeries rather than patients. The final decision was to exclude second eye surgeries done within 28 days of first eye surgeries, but to rerandomize all other second eye surgeries. Differences in event rates between treatment groups can be estimated using Generalized Estimating Equations, and the association between outcomes of first and second eye operations estimated with pairwise odds ratios. An anticipated small positive correlation is likely to have minimal impact on statistical power and effective sample size.

Cataract↗

PubMed1997

Prevalence and risk factors for refractive errors in an adult inner city population.

PURPOSE: To estimate the prevalence of refractive errors among adult black and white Americans and to identify risk factors associated with these refractive errors. METHODS: Refractive error was measured in a population-based sample of black and white adults age 40 or older residing in east Baltimore from 1985 through 1988. Aphakic eyes were excluded from analysis. RESULTS: The prevalence of myopia varied from 10.5% among black men 80 years and older to 42.1% among white women 40 to 49 years of age. Hyperopia ranged from 11.8% among black men 40 to 49 years to 68.1% among white men 80 years of age and older. Astigmatism ranged from 15.8% to 45.2%, and anisometropia ranged from 2.8% to 8.1%, depending on age, race, and gender. Black persons had less myopia, hyperopia, astigmatism, and anisometropia than did white persons. Myopia (< -0.5 diopter [D] spherical equivalent) declined with age, whereas hyperopia (> +0.5 D), astigmatism (> 0.5 D of cylinder), and anisometropia (> 1.0 D between eyes) increased with age. Myopia increased with increasing years of education, although this association was stronger for white persons than for black persons and among younger subjects. Hyperopia declined with increasing years of education, and this association was stronger among younger than older subjects. Education was not associated with astigmatism or anisometropia. CONCLUSIONS: Black persons had lower rates of refractive error than did white persons, except for hyperopia prevalence, which was comparable in black and white women. Refractive errors are common among adult inner city Americans, but rates vary substantially by age, race, gender, and education levels.

Adult↗

PubMed1997

Parasitic infections in Pemba Island school children.

Intestinal helminths, schistosomiasis and malaria have been recognised for decades to be major public health problems in Zanzibar, Tanzania. During the evaluation of the impact of the Zanzibar Helminth Control Programme, baseline parasitological data on 3,605 school children were collected in Pemba Island. Prevalence of intestinal helminth infections was 72%, 94% and 96% for Ascaris lumbricoides, Trichuris trichiura and hookworm, respectively. Thirty one percent of children tested positive for haematuria, a reliable indicator of urinary schistosomiasis in the study area. Malaria parasites were found in 61% of children. Hookworm infections and haematuria were more prevalent in boys. Sixty seven percent of the children were infected with all the three helminths, and 28% harboured double infection. No association was found between intestinal helminths and schistosomiasis or malaria. Children living in rural areas were more heavily infected with hookworms, schistosomiasis and malaria compared to children in towns. Results from this study provided relevant information for designing a "plan of action" for the integrated control of filariasis, intestinal helminths, malaria and schistosomiasis in Zanzibar.

Adolescent↗

PubMed1997

Self-reported assessment of dry eye in a population-based setting.

PURPOSE: To report on a subjective dry eye assessment method for use in large-scale research, to evaluate its application in a population-based study of dry eye among elderly persons in the United States, and to apply novel techniques to improve simple questionnaire item summaries. METHODS: A dry eye questionnaire was administered to a population-based sample of 2520 volunteers ages 65 to 84 years in Salisbury, Maryland. Individual symptoms and signs, counts of symptoms and signs, and latent class model summary of item responses were evaluated for validity and internal consistency. RESULTS: Approximately 15% of participants reported experiencing one or more of six dry eye symptoms often or all the time; 20% reported experiencing three or more symptoms sometimes, often or all the time. Four groups were derived on the basis of symptomatology, using latent class analysis. The groups exhibited face validity, revealed symptom patterns that added specificity to simple symptom counts, and were qualitatively similar when derived separately within population subgroups. Internal consistency was moderate (Cronbach's alpha = 0.61), indicating some variability in reporting. CONCLUSIONS: Dry eye symptoms are commonly reported in a representative elderly population. Symptom data were moderately consistent, suggesting their usefulness for dry eye assessment if properly summarized. A latent class summary revealed biologically meaningful summary patterns of symptoms reported in this population and holds promise for use in risk factor investigations and in clinical trials.

Aged↗