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Biomedical subjects

D J Aaron

Publications and source records attributed to D J Aaron.

At least 19 recordsLinked to original sources
PubMed2003

Estimating the lesbian population: a capture-recapture approach.

STUDY OBJECTIVE: Little is known about the number of women who identify as lesbian. Estimates from the US range from 1% to nearly 10%. Accurate estimates are critical in order to meet lesbian's healthcare needs and to address health problems that may be more prevalent among them. This study used capture-recapture methods to estimate the lesbian population of Allegheny County, Pennsylvania. DESIGN: Mailing lists from four sources were used to identify lesbians. The capture-recapture method and log-linear modelling were used to estimate the number of lesbians in the defined geographical area, and the percentage of the female population they comprised there was determined through census data. SETTING: Allegheny County, Pennsylvania, USA. RESULTS: A total of 2185 unique names were identified. The capture-recapture method estimated that the total lesbian population of Allegheny County was 7031 (95% CI 5850 to 8576). Therefore, based on the 1990 census figures, the county's adult lesbian population was estimated to be 1.87% (95% CI 1.56% to 2.28%) of the adult female population. CONCLUSIONS: An estimate of the lesbian population is fundamental for addressing lesbian's health needs and for developing appropriate research programmes. Capture-recapture methods have the potential to provide accurate and reliable estimates of this population in any location.

Adult↗
PubMed2001

Does the perception of downloading speed influence the evaluation of web-based lectures?

Medical schools put little emphasis upon education on public health, even though public health has played an important role in this century. One way to harness its benefit in order to improve global health in the 21st century is to globally share lectures on public health through the Internet. We have developed the Supercourse comprising of web-based learning modules on epidemiology in a standardized format with the size of each web page less than 10 kilobytes. A cross-sectional observational study was conducted to investigate the association of the perception of the access speed to Web-based lectures by teachers with their perception of lecture quality. There were 223 teachers who rated the lectures: 72% were from North America or Western Europe, 40% had taught epidemiology, and 14% reported that the speed of access was slow. Odds ratio of above-average rating among those who reported that the speed of access was fast relative to those who reported that the speed of access was slow was 4.25 (2.03-8.91; P = 0.001). The odds ratios were similar and significant after taking into account several other factors, including the variation of rating across lectures, region, and experiences in teaching epidemiology. The results indicate that the perception of the quality of Web-based lectures is related to the speed of access to a web page. The speed of access may be as important, if not more important, as the content itself. This suggests that, to share educational materials on the Web globally for teachers, one must consider not only the content, but also how people at local sites gain access to the Internet.

Cross-Sectional Studies↗
PubMed2001

Behavioral risk factors for disease and preventive health practices among lesbians.

OBJECTIVES: This study compared the prevalence of health behaviors among lesbians and in the general population of women. METHODS: We used a cross-sectional community-based survey of 1010 self-identified lesbians 18 years or older. RESULTS: Compared with the general population of women, lesbians were more likely to report cigarette use, alcohol use, and heavy alcohol use. A higher percentage of lesbians were categorized as overweight, and lesbians were more likely to participate in vigorous physical activity. They were less likely to report having had a Papanicolaou test within the past 2 years but more likely to report ever having had a mammogram. CONCLUSIONS: While there may be differences in health behaviors between lesbians and the general population of women, how these differences influence the risk of subsequent disease is unknown.

Adolescent↗
PubMed2000

Longitudinal changes in physical activity in a biracial cohort during adolescence.

PURPOSE: This report describes the development and use of two self-report methods and an objective measure to assess longitudinal changes in physical activity in a large biethnic cohort of young girls from childhood through adolescence. METHODS: The NHLBI Growth and Health Study (NGHS) is a multicenter study of obesity development in 2379 black and white girls followed from ages 9-10 yr to 18-19 yr (NGHS years 1-10). A Caltrac activity monitor was used to objectively quantify activity levels in years 3-5. A 3-d diary (AD) and a habitual patterns questionnaire (HAQ) were administered annually and biannually, respectively, to subjectively quantify physical activity levels. The changing pattern of activities as the girls matured during the 10-yr study period necessitated periodic form changes. Empirical analytic approaches were developed to help distinguish between true longitudinal changes in activity levels from potential numerical artifacts resulting from modifications in forms. RESULTS: The longitudinal activity data indicate a steep decline in the level of reported activity from baseline to year 10 as indicated by AD scores (446.8 to 292.1 MET-min x d(-1), 35%) as well as by HAQ scores (29.3 to 4.9 MET-times x wk(-1), 83%). This parallel trend in the pattern of the decline in activity among the two self-report methods was mirrored by a similar decline using the Caltrac method of physical activity assessment. From years 3 to 5, the AD decreased by 22%, whereas both the HAQ and Caltrac declined by 21%. CONCLUSION: The longitudinal data on physical activity collected in the NGHS cohort further confirm a dramatic decrease in the overall level of physical activity during the transition from childhood to adolescence. The consistency among the three methods indicate that both the AD and HAQ are useful tools for the assessment of activity levels in adolescent girls.

Adolescent↗
PubMed1995

Efficiency and accuracy of disease monitoring systems: application of capture-recapture methods to injury monitoring.

Capture-recapture methods were employed to determine the most accurate and efficient approaches to monitor adolescent injuries. Multiple sources were used to ascertain cases of adolescent injuries that occurred between September 1 and December 31, 1991, in a single school district in metropolitan Pittsburgh, Pennsylvania. Eliminating the duplicate cases between the sources revealed 144 verified injuries; 127 (88.2%) were identified by student monthly recalls, 33 (22.9%) by daily attendance records, 58 (40.3%) by medical excuses, and 72 (50.0%) by a 4-month student recall. Capture-recapture analyses were undertaken to assess potential dependencies between the sources, to estimate the degree of underascertainment in the population, and to evaluate the efficiency of the individual sources and the combinations between them. It was estimated that 91% of the cases in the population were ascertained when all four methods of case finding were utilized. Furthermore, the analysis indicated that accurate injury estimates could be achieved using combinations of only two or three of the sources. An analysis of the efficiency of the methods of ascertainment revealed a trade-off between effort (the number of hours needed to identify cases) and the precision (coefficient of variation) of the injury estimates. Capture-recapture analysis not only provided an approach to evaluate and adjust for undercount but also offered a formal means to evaluate the most efficient combination of the sources to maximize completeness while minimizing effort. The use of these techniques has the potential to evaluate and improve injury surveillance as well as other disease monitoring systems.

Adolescent↗
PubMed1995

Reproducibility and validity of an epidemiologic questionnaire to assess past year physical activity in adolescents.

The reproducibility and validity of a past year physical activity questionnaire was determined in a sample of 100 adolescents aged 15-18 years, randomly selected from a population-based cohort. Subjects completed four 7-day recalls of activity approximately 3 months apart. The average of the four 7-day recalls of activity was utilized as the "gold standard" against which the past year questionnaire was compared to evaluate validity. The questionnaire was also validated against objective measures, such as physical fitness and body mass index. Interscholastic team rosters were utilized to directly validate the reporting of specific activities. One-month and one-year test-retest reproducibility of the questionnaire were determined. For different measures of activity, the Spearman correlations between the questionnaire and the average of the 7-day recalls ranged from 0.55 to 0.67 in males and 0.73 to 0.83 in females, all significant at p < 0.01. In general, although there was no association between the past year activity questionnaire results and objective measures, there was a significant, albeit weak association between the physical activity questionnaire and time to complete a 1-mile (1.61-km) run (r = -0.47) in females. Subjects reported participating in specific interscholastic sports with an accuracy of 100%, 86%, and 95% for the fall, winter, and spring sports, respectively. Test-retest reproducibility was higher over one month (r = 0.79) than over one year (r = 0.66). These data provide evidence that the questionnaire yields a reasonable estimate of past year or "habitual" physical activity in adolescents.

Adolescent↗
PubMed1995

Physical activity and the initiation of high-risk health behaviors in adolescents.

The association of physical activity to the initiation of health risk behaviors was examined in a 3-yr prospective study of a population-based cohort of 1245 adolescents aged 12-16 yr. Four hundred thirty-seven students (35% of the cohort) were identified at baseline via self-report survey as never having smoked cigarettes, consumed alcohol, used marijuana, or carried a weapon. Three measures of physical activity were obtained at baseline: leisure-time physical activity (LTPA), level of aerobic fitness (AF), and participation in competitive athletics. Significant associations, with notable gender differences, were observed between physical activity and the initiation of cigarette smoking and alcohol use. The cumulative proportion of male students initiating alcohol use was 48%, 42%, and 24% for high, moderate, and low LTPA, respectively (P < 0.01). Males who participated in competitive athletics were significantly more likely than nonathletes to initiate alcohol use (44% vs 17%, P < 0.01). The cumulative proportion of female students initiating cigarette use was 10%, 23%, and 22% for high, moderate, and low LTPA, respectively (P < 0.05) and 7%, 28%, and 16% for high, moderate, and low AF, respectively (P < 0.05). No association was found between physical activity and weapon carrying. These results indicate that in this cohort of adolescents, the most active or most fit females were less likely to initiate cigarette smoking. In contrast, the most active males or males who participated in competitive athletics appeared more at-risk for initiating alcohol consumption than their less active counterparts.

Adolescent↗
PubMed1994

The role of socioeconomic status and injury morbidity risk in adolescents.

OBJECTIVE: To examine the patterns of socioeconomic status and injury morbidity in adolescents. DESIGN: Prospective cohort study. SETTING: Metropolitan school district in Allegheny County, Pennsylvania. PARTICIPANTS: There were 1245 students (89%) recruited from 1400 aged 12 to 16 years. INTERVENTIONS: None. MEASURES AND RESULTS: Baseline variables of socioeconomic status used for this analysis included township of residence (from the 1990 census data ranked by the percentage of households below the poverty level) and employment status of the parents (student self-report). Life-table analysis revealed no differential risk of injury by socioeconomic status. Similar results were found when stratified by gender, race, injury type (sport vs nonsport), and injury place (school vs home). CONCLUSIONS: The results indicate that in this cohort of adolescents, socioeconomic status does not seem to be a contributing risk factor for injury.

Adolescent↗
PubMed1993

The epidemiology of leisure physical activity in an adolescent population.

A cohort of 1245 adolescents, 12-16 yr old and participating in a prospective study of risk factors for injury, were surveyed annually to assess past year leisure physical activity. This report describes the development and reproducibility of the questionnaire and provides the descriptive epidemiology of leisure physical activity in adolescents. The questionnaire was self-administered twice, a year apart, and had a 1 yr test-retest rank order correlation of 0.55. The past year estimate of leisure activity was also shown to be related to fitness (rho = -0.37), which was defined as the time needed to complete a 1-mile run. Males reported significantly more activity than females (P < 0.05) and whites reported more activity than nonwhites (P < 0.05). However, socioeconomic status was not found to be a determinant of activity levels in either males or females. In females, a negative association between activity and age was found (P < 0.05); however, this association was not evident in males. In summary, an activity questionnaire has been developed and was shown to be both reproducible and feasible. Therefore, it was used to examine habitual leisure physical activity patterns of adolescents.

Adolescent↗
PubMed1993

Surveillance of serious recreational injuries: a capture-recapture approach.

Serious injury from sport and recreation is a leading cause of morbidity and mortality in the United States. Historically, occurrences of diseases with substantial public health impact have been monitored via surveillance systems in order to obtain information concerning the frequency with which the diseases occur. Surveillance leads to efforts that identify risk factors, and eventually, control measures to reduce the incidence of disease. Currently, the surveillance of sports injury represents only limited coverage in the U.S. It is important to begin discussions regarding approaches toward the development of surveillance of these injuries. Methods based upon the communicable disease surveillance model could potentially be used to monitor serious sports injuries. One method of surveillance, using the statistical approach of capture-mark-recapture, is presented as an example by which a national system of surveillance of serious sports injury could be established.

Athletic Injuries↗
PubMed1992

The epidemiology of low back pain in an adolescent population.

We assessed the prevalence of low back pain (LBP) in a cohort of 1242 adolescents (aged 11 through 17) currently participating in a 4-year prospective study of medically treated injuries. Overall, 30.4% of the adolescents reported LBP. The impact of LBP in adolescents was considerable, with one third resulting in restricted activity and 7.3% seeking medical attention. Life-table analysis demonstrated that by age 15, the prevalence of LBP increased to 36%. There were few differences by gender or race. These results suggest that LBP in adolescents is a serious public health problem.

Absenteeism↗