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Biomedical subjects

J M Tielsch

Publications and source records attributed to J M Tielsch.

At least 127 records · Page 7Linked to original sources
PubMed1990

Determinants of hospital charges and length of stay for ocular trauma.

Ocular trauma is an important cause of blindness and visual impairment in the United States. This study examined the economic effect of ocular trauma by evaluating hospital length of stay and charges for 4406 discharges from Maryland hospitals from 1979 to 1986. Length of stay declined on average 6.1% per year during this period. Length of stay was positively associated with age which could not be accounted for by the severity of the trauma or the presence of secondary trauma diagnoses. Other factors associated with length of stay included race, principal diagnosis, secondary trauma, and characteristics of the hospital. National projections estimate greater than 227,000 hospital days and $175 to $200 million in hospital charges alone are due to ocular injuries every year.

Adolescent↗
PubMed1989

Time trends in the incidence of hospitalized ocular trauma.

Ocular trauma is an important cause of blindness and visual impairment in the United States. We examined the incidence of hospitalized ocular trauma in Maryland from 1979 through 1986 using hospital discharge abstracts. The annual incidence for those with definite ocular trauma (principal diagnosis) was 13.2 per 100,000 population and for total ocular trauma (principal or secondary diagnoses), 27.3 per 100,000. There was a 25% decline in incidence of definite ocular trauma over this eight-year period; however, this was likely due to changing indications for hospitalization. The pattern of risk by age was bimodal, with peaks in the 15- to 29-year and over-70-year age categories. Males were at higher risk than females except in the oldest age groups, and nonwhites had higher rates than whites.

Adolescent↗
PubMed1988

Intraobserver and interobserver agreement in measurement of optic disc characteristics.

Reliable measures of optic nerve status are important parameters for epidemiologic and clinical studies of glaucoma. Stereo fundus photography has been used to reduce interobserver variation, but little data have been reported quantifying the level of agreement in these situations. This article examines chance-corrected intraobserver and interobserver agreement for horizontal and vertical cup:disc ratios and width of the narrowest remaining neuroretinal rim on stereo, color, fundus photographs. Intraobserver agreement was substantial to almost perfect for both readers (kappas between 0.82 and 0.86 for horizontal and vertical cup:disc ratios and 0.71 for the neuroretinal rim). Interobserver agreement was also substantial (kappas of 0.71 for horizontal cup:disc ratio, 0.74 for vertical cup:disc ratio, and 0.58 for the neuroretinal rim). Both intraobserver and interobserver agreement were best for glaucoma patients followed by ocular hypertensives and controls. Dichotimizing cup:disc ratios into suspicious or not suspicious using a range of cutoff points (greater than or equal to 0.5, greater than or equal to 0.6, and greater than or equal to 0.7 disc diameters [DD]) had little effect on agreement levels. Estimation of the status of the optic nerve is complex, requiring judgment about the shape and structure of the cup. Agreement is optimized by using stereo photographs, using the same observer and, when evaluating progression, comparing photographs from different points in time at a single sitting.

Glaucoma↗
PubMed1988

Village and household clustering of xerophthalmia and trachoma.

The clustering of xerophthalmia in villages and in households was assessed among preschool children surveyed in the Lower Shire Valley, Malawi, and in Aceh province, Indonesia. Trachoma clustering was similarly assessed among the same children in Malawi. Trachoma clustered much more than xerophthalmia among villages and among households. The impact of xerophthalmia clustering on sample size considerations for future surveys or interventions was similar in Malawi and Indonesia. Village clustering of xerophthalmia would necessitate a twofold increase in sample size. Household clustering in the absence of village clustering would have almost no impact on sample size. Village clustering of trachoma would necessitate a ninefold increase in sample size. Household clustering would increase sample size requirements by 26%.

Child, Preschool↗
PubMed1988

The epidemiology of trachoma in southern Malawi.

A population-based prevalence survey of ocular disease was conducted in the Lower Shire River Valley of Malawi in 1983. A total of 5,436 children less than 6 years of age and 1,664 persons greater than or equal to 6 years were examined. The prevalence of inflammatory trachoma peaked in the 1-2-year-old age group at 48.7% and declined rapidly with age to less than 5% by age 15. The prevalence of cicatricial trachoma was low in young children and climbed gradually with age to greater than 40% among those greater than or equal to 50 years. Risk factors for inflammatory disease in young children included low socioeconomic status of the family, long walking distance to the household's primary source of water, absence of a latrine in the family compound, and presence of trachoma among siblings. Indices of crowding practices were not associated with inflammatory disease. An apparent inverse association of facewashing and inflammatory trachoma in children did not hold up when adjusted for other risk factors.

Adolescent↗
PubMed1987

The prevalence of glaucoma among Eskimos of northwest Alaska.

Data collected during a population-based general ophthalmic prevalence survey among Alaska's northwestern Eskimos were analyzed to determine the prevalence of glaucoma. Of the 1686 Eskimos examined, 11 cases (0.65%) of glaucoma were found, including ten cases of angle closure glaucoma (both chronic and acute forms) and a single case of open angle glaucoma. This indicates the rarity of open angle glaucoma in Eskimo eyes and a reversal of the typical pattern found in the general US population. Narrow angle glaucoma occurred at a rate of 2.65% in Eskimos older than 40 years of age, the prevalence increasing with age in both sexes. Women were afflicted almost four times as often as men, and the sex difference persisted across all age groups. Anterior chamber angles appeared clinically narrower with age and among women. Seventeen percent of all Eskimos older than 50 years had occludable angles by gonioscopy. These findings target older Eskimo women as a group particularly at risk for angle closure glaucoma.

Adult↗
PubMed1987

Acquired disorders affecting the immune system and non-Hodgkin's lymphoma.

A case-control study was undertaken to determine whether a prior history of a variety of acquired disorders affecting the immune system was associated with an increased risk of non-Hodgkin's lymphoma. Cases were identified over a 4-year period (1976-1979) at the Johns Hopkins Hospital and individually matched to hospital controls on age, sex, race, and year of diagnosis. For the 109 cases and matched controls who were traced and interviewed, positive associations suggesting an increase in risk were not detected. Instead, there was a suggestion of an inverse relationship. Odds ratios (ORs) were consistently less than 1 for associations between non-Hodgkin's lymphoma and several chronic infectious diseases (OR = 0.65, 95% CI = 0.35, 1.20), chronic inflammatory diseases (OR = 0.88, 95% CI = 0.43, 1.79), autoimmune disorders (OR = 0.80, 95% CI = 0.19, 3.76), and allergic disorders (OR = 0.77, 95% CI = 0.45, 1.32). A statistically significant protective association was found for surgical removal of lymphoid tissue (OR = 0.50, 95% CI = 0.27, 0.91). Adjustment for potentially confounding variables did not change these results. These findings do not support the previously anecdotally reported impression that disorders producing a chronic antigenic stimulus are associated with the development of non-Hodgkin's lymphoma.

Adolescent↗
PubMed1987

Trachoma grading: observer trials conducted in southern Malawi.

A variety of grading schemes have been proposed for the clinical classification of inflammatory trachoma. During a population based study of ocular disease conducted in southern Malawi we tested a simplified version of the current WHO grading scheme. Intraobserver agreement statistics were less than satisfactory for three of four graders. Interobserver agreement when compared against either a well experienced standard ophthalmologist or a consensus grade improved over time for two of the three graders. However, initial agreement for all three graders was only fair to moderate. Previous studies of trachoma grading schemes support these unsatisfactory results. A new system of classification is needed that is both accurate and reliable in a field setting.

Adult↗
PubMed1986

Direct-smear fluorescent antibody cytology as a field diagnostic tool for trachoma.

A recently developed direct-smear fluorescent antibody (DFA) cytology method of detecting chlamydial infection was evaluated in an area where trachoma is endemic. Four hundred seventy-five children aged 2 to 10 years were examined, and adequate conjunctival cytology specimens were collected from 457 (96%). Trachomatous inflammatory changes were observed in 114 (25%) of the children. The DFA cytologic technique has a high specificity (100%) but a low sensitivity (8%). It offers a number of advantages over existing laboratory methods for diagnosing trachoma in the field. It is a rapid, simple, and easily transferred test that has a high specificity. Although DFA cytology shares the low sensitivity of other laboratory methods of diagnosing trachoma, we believe its logistical advantages make it the laboratory test of choice.

Antibodies, Monoclonal↗
PubMed1986

Prevalence and severity of xerophthalmia in southern Malawi.

The first population-based study of xerophthalmia in Africa was conducted in the Lower Shire River Valley of Malawi in the autumn of 1983. A total of 5,436 children under six years of age were examined by three survey teams over an eight-week period. The prevalence of active xerophthalmia was 3.9%. Rates for night blindness and active corneal disease were more than five times the World Health Organization criterion for a problem of public health importance. Xerophthalmic corneal scarring occurred at a rate of 5.9/1,000, more than 10 times the World Health Organization criterion. All cases of bilateral blindness in this age group were considered to be due to vitamin A deficiency. Given recent evidence from Asia linking even subclinical vitamin A deficiency to increased risk of mortality and morbidity, this disease is not only a leading cause of blindness in this area, but may have an important impact on child survival as well.

Child, Preschool↗
PubMed1986

Chronic lymphocytic leukemia and acquired disorders affecting the immune system: a case-control study.

The relationship of a number of subacute or chronic infectious diseases, connective tissue or autoimmune disorders, allergic conditions, and surgical excision of lymphoid tissue with chronic lymphocytic leukemia (CLL) was examined in a case-control study involving 342 cases and 342 matched controls. In both analyses of all matched pairs and those pairs in which both subjects were respondents, no statistically significant association was found between a history of subacute viral infections or subacute and chronic bacterial infections and CLL. Connective tissue or autoimmune disorders also were found not to be associated with CLL. Examination of the association between several allergic conditions and CLL suggested a protective effect as did a "dose-response" analysis, although none of the individual disorders showed a statistically significant relationship; however, a test for linear trend was significant (P = .04). Similarly, examination of the relationship between surgical excision of lymphoid tissue in several anatomic locations and CLL showed a protective effect, statistically significant for tonsillectomy-adenoidectomy (odds ratio = 0.69; 95% confidence interval = 0.48, 0.98). A statistically significant negative dose-response relationship, substantiating the protectiveness of the effect, was found.

Aged↗
PubMed1986

Blindness and visual impairment in southern Malawi.

There is a paucity of reliable information on the prevalence and causes of blindness in sub-Saharan Africa, and this produces problems in designing and evaluating blindness prevention programmes. To address this problem and to provide baseline data for the evaluation of such programmes, the government of Malawi, in conjunction with a number of agencies, conducted a population-based prevalence survey of ocular disease in the Lower Shire River Valley in southern Malawi, an area where blindness is common. The prevalence of bilateral blindness found (1.27%) is similar to that in other developing countries and represents a significant public health problem. At least 60% of this blindness is preventable or easily reversible.

Adult↗
PubMed1986

Incidence of aplastic anemia in a three county area in South Carolina.

An apparent cluster of four aplastic anemia (AA) cases in teenagers residing in a small South Carolina town was further investigated. Incidence of AA in all age groups in a surrounding three county area (TCA) over a 12-year time interval was determined and compared with AA incidence rates in Baltimore, representing the only known population based United States incidence data. The same general age-specific incidence pattern (based on 27 cases in the TCA and 118 in Baltimore) was found in the two areas, both overall and for the four race-sex groups. Although based on small numbers, nonwhite average annual age-adjusted rates for males and females were higher in the TCA (6.8 and 13.7 per million) than in Baltimore (4.7 and 7.3). For whites, TCA rates were 11.7 and 5.4 (for males and females) and Baltimore rates were 7.1 and 5.4. The differences for non-whites in the two areas may indicate a greater prevalence of risk factors for AA in the TCA than in Baltimore, but the small numbers of cases and the lack of comparable data from other areas of the country, together with the possibility of misdiagnosis of the disease, make definitive conclusions impossible.

Age Factors↗
PubMed1985

An apparent cluster of aplastic anemia in a small population of teenagers.

Four teenagers with severe aplastic anemia, initially diagnosed and evaluated over a seven-year period at The Johns Hopkins Bone Marrow Transplant Unit, Baltimore, were residents of the same small town in South Carolina. Estimated annual incidence for that age group in the town, based on the four cases, was 100 times the expected rate. All four of the teenagers had attended one of two junior high schools. An exploratory survey of all high-school students, comparing risk factors of those who had attended the "affected" junior high school with those who had attended the "unaffected" junior high school, showed no associations with exposure to glue, paint or varnishes, pesticides, history of hepatitis or infectious mononucleosis, or use of chloramphenicol or other suspected drugs. Weak associations were found between the affected junior high school and employment in the textile industry and in agriculture (specifically peach orchards).

Adolescent↗
PubMedDate not supplied

Cost and efficiency considerations in community-based trials of vitamin A in developing countries.

Recent investigations conducted in Indonesia have identified an important role for adequate vitamin A nutriture in preventing mortality in young children. A randomized, community-based trial of vitamin A supplementation in northern Sumatra demonstrated a 34 per cent reduction in mortality among pre-school aged children who received twice yearly vitamin A supplementation. These results have stimulated renewed interest in vitamin A as a potentially important mediator of improved child survival. Cost and efficiency considerations are important in these types of trials but must be balanced with logistical constraints that are unique to these environments. A number of these issues are discussed and some general guidelines are proposed for such investigations.

Child, Preschool↗
PubMedDate not supplied

Retinal microvascular abnormalities and their relationship with hypertension, cardiovascular disease, and mortality.

Retinal microvascular abnormalities, such as generalized and focal arteriolar narrowing, arteriovenous nicking and retinopathy, reflect cumulative vascular damage from hypertension, aging, and other processes. Epidemiological studies indicate that these abnormalities can be observed in 2-15% of the nondiabetic general population and are strongly and consistently associated with elevated blood pressure. Generalized arteriolar narrowing and arteriovenous nicking also appear to be irreversible long-term markers of hypertension, related not only to current but past blood pressure levels as well. There are data supporting an association between retinal microvascular abnormalities and stroke, but there is no convincing evidence of an independent or direct association with atherosclerosis, ischemic heart disease, or cardiovascular mortality. New computer-related imaging methods are currently being developed to detect the presence and severity of retinal arteriolar narrowing and other microvascular characteristics. When reliably quantified, retinal microvascular abnormalities may be useful as risk indicators for cerebrovascular diseases.

Cardiovascular Diseases↗