Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “sampling design”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed2002

Factors affecting uptake of cervical and breast cancer screening among perimenopausal women in Hong Kong.

OBJECTIVES: To identify factors affecting cervical and breast cancer screening attendance among women aged 44 to 55 years by comparing self-reported uptake of cervical smear and clinical breast examination between patients and a population sample. DESIGN AND SETTING: Telephone survey and audit of clinic records to confirm patients' self-report. PARTICIPANTS: Two thousand and sixty-seven women identified through random telephone dialling from the residence directory and 319 patients ever-registered at a family practice teaching clinic. MAIN OUTCOME MEASURES: Uptake of cervical smear and clinical breast examination. RESULTS: The proportion of women undergoing cervical smear tests and clinical breast examination in the previous 12 months were 35.4% and 22.6%, respectively, for randomly selected women, while the figures were 47.2% and 50.6%, respectively, for patients. Record audit confirmed high rates of screening for patients according to evidence-based protocols (85.1% had had a cervical smear within 3 years). For women in the random sample (mean age, 48.9 years; standard deviation, 3.3 years), those who were older, postmenopausal, not receiving hormone therapy, educated to primary level, and with no chronic diseases were least likely to have had screening. For clinic patients (mean age, 47.9 years; standard deviation, 2.8 years), lower education level was the only variable associated with no recent smears. CONCLUSIONS: Healthy perimenopausal and postmenopausal women in the community with lower educational level and not receiving hormone therapy were more likely to be underscreened. Attendance of 44- to 55-year-old women at a family medicine clinic that actively promotes preventive medicine was associated with high screening uptake.

Adult↗
PubMed1999

Destructive periodontal disease in adults 30 years of age and older in the United States, 1988-1994.

BACKGROUND: Accurate information on the prevalence and extent of periodontal diseases in the United States adult population is lacking. This study estimated the prevalence and extent of periodontal disease in the United States using data from the third National Health and Nutrition Examination Survey (NHANES III). METHODS: A nationally representative sample was obtained during 1988 to 1994 by a stratified, multi-stage probability sampling design. A subsample of 9,689 dentate persons 30 to 90 years old who received a periodontal examination was used in this study, representing approximately 105.8 million civilian, non-institutionalized Americans in 1988 to 1994. Periodontal attachment loss, probing depth, and furcation involvement were assessed in 2 randomly selected quadrants per person. Attachment loss and probing depth were assessed at 2 sites per tooth, the mesiobuccal and mid-buccal surfaces. The periodontal status of each subject was assessed by criteria based on the extent and severity of probing depth and furcation involvement. These assessments were used to classify each subject as having a mild, moderate, or advanced form of the disease. In the analyses, weighted data were used to reflect the complex sampling method. RESULTS: Prevalence of attachment loss > or = 3 mm was 53.1% for the population of dentate U.S. adults 30 to 90 years of age and, on average, 19.6% of teeth per person were affected. The prevalence of probing depth > or = 3 mm was 63.9% and, on average, 19.6% of teeth were affected. Fourteen percent of these persons had furcation involvement in one or more teeth. We estimate that at least 35% of the dentate U.S. adults aged 30 to 90 have periodontitis, with 21.8% having a mild form and 12.6% having a moderate or severe form. The prevalence and extent of attachment loss and the prevalence of periodontitis increase considerably with age. However, the prevalence of moderate and advanced periodontitis decreases in adults 80 years of age and older. This is most likely attributed to a combination of a high prevalence of tooth loss and gingival recession in the oldest age cohorts. Attachment loss and destructive periodontitis were consistently more prevalent in males than females, and more prevalent in blacks and Mexican Americans than whites. We estimate that in persons 30 years and older, there are approximately 56.2 and 67.6 million persons who, on average, have about a third of their remaining teeth affected by > or = 3 mm attachment loss and probing depth, respectively. We also estimate that about 21 million persons have at least one site with > or = 5 mm attachment loss, and 35.7 million persons have periodontitis. These are conservative estimates based on partial-mouth examinations, and the true prevalence and extent of periodontal disease may be significantly higher than what is reported here. CONCLUSIONS: Periodontitis is prevalent in the U.S. adult population. The results show that black and Mexican American males have poorer periodontal health than the rest of the U.S. adult population. Primary and secondary preventive measures should therefore be specifically targeted towards these groups.

Adult↗
PubMed2006

Failure monitoring in water distribution networks.

An algorithm for the burst detection and location in water distribution networks based on the continuous monitoring of the flow rate at the entry point of the network and the pressure at a number of points within the network is presented. The approach is designed for medium to large bursts with opening times in the order of a few minutes and is suitable for networks of relatively small size, such as district metered areas (DMAs). The burst-induced increase in the inlet flow rate is detected using the modified cumulative sum (CUSUM) change detection test. Based on parameters obtained from the CUSUM test, the burst is simulated at a number of burst candidate locations. The calculated changes in pressure at the pressure monitoring points are then compared to the measured values and the location resulting in the best fit is selected as the burst location. The EPANET steady-state hydraulic solver is utilised to simulate the flows and pressures in the network. A sensitivity-based sampling design procedure is introduced to find the optimal positions for pressure monitoring points. The proposed algorithm is tested on a case study example network and shows potential for burst detection and location in real water distribution systems.

Algorithms↗
PubMed1999

The efficacy of psychosocial approaches to behaviour disorders in dementia: a systematic literature review.

OBJECTIVE: This paper provides a systematic review of research findings published between 1989 and 1998 concerning non-pharmacological strategies to alleviate behavioural disturbances in elderly persons with dementia. METHOD: Data collection strategies included computer literature searches, manual searches of selected journals and checks of references listed in previous reviews. To warrant inclusion, studies were required to include some measure of behaviour before and after the introduction of an intervention. Papers were appraised in the following domains: design, sampling technique, setting, behaviours studied, measurement tools, data collection methods, type of interventions and feasibility. An overall validity rating was assigned to each article using predetermined rules. RESULTS: Forty-three studies met criteria for inclusion including five randomised controlled trials. Validity ratings were as follows: one strong, 15 moderate, and 27 weak. Areas of scientific weakness included small numbers of subjects, inadequate descriptions of study participants, imprecise data collection methods, high attrition rates and insufficient statistical analysis. Despite this, there is evidence to support the efficacy of activity programs, music, behaviour therapy, light therapy, carer education and changes to the physical environment. The evidence in favour of multidisciplinary teams, massage and aromatherapy is inconclusive. CONCLUSIONS: It was easier to interpret the results of rigorously designed studies that focused on a single behaviour or single intervention tailored to the needs of individuals and carers. Future studies should seek to replicate the findings outlined here, improving methodologies where necessary and including outcome measures that encompass the interests of people with dementia, family caregivers and health professionals.

Aged↗
PubMed2003

Evidence for the independence of positive and negative well-being: implications for quality of life assessment.

OBJECTIVES: Evidence is accumulating that positive mental states are more than the absence of symptoms, and may play an independent role in health outcomes. The aim of this study is to compare the characteristics and determinants of positive and negative mental states in a population sample. DESIGN: A novel analysis of data was undertaken from the General Health Questionnaire (GHQ-30) which was completed by 6,317 participants in the Health and Lifestyle Survey at Time 1 and 3,778 at Time 2, 7 years later. METHODS: We derived a positive well-being scale (POS-GHQ) based on positive responses to the positive items of the GHQ-30, and compared it to a standard symptom measure (CGHQ). Discriminant function analyses were performed to establish which demographic, health and social variables best accounted for scores on each scale. RESULTS: The distributional properties of the two scales, together with the results of the discriminant analyses, demonstrate a degree of independence between positive and negative well-being. Over one third of the sample obtained either low scores on both positive and negative well-being measures or high scores on both measures. Disability and lack of social roles were important determinants of psychological symptoms, but had less influence on positive well-being. Having paid employment was an important determinant of positive well-being but had less influence on psychological symptoms. We also found that 7-year mortality was predicted more strongly by the absence of positive well-being than by the presence of psychological symptoms. CONCLUSIONS: These findings point to the need to include measures of positive well-being in studies of health outcomes and quality of life assessment.

Adolescent↗
PubMed1993

Design and analysis of drug safety studies, with special reference to sporadic drug use and acute adverse reactions.

A methodological approach for analysis of drug safety data which permits the calculation of risk measures for intermittent exposures and acute adverse reactions is presented. This method allows for the observation of exposures that are temporary and which may be of varying lengths, as in the application of analgesics. Risk measures are determined using the relative risk and the excess risk to assess drug safety. The latter has important public health policy significance for decision making about the safety of a drug. The model depends on a simple counting process and allows for the consideration of concomitant variables which can likewise exert an influence on the absolute risk. Hazard estimates are derived by the maximum likelihood method. Three possible approaches to the planning and analysis of studies of drug safety are discussed: cohort studies, case-cohort studies, and case studies. The case study represents an approach which requires only data from the individuals in which an adverse reaction has occurred. The different sampling designs are illustrated using data from a study investigating the etiology of wound healing disorders.

Acute Disease↗
PubMed2004

Lactation among adolescent mothers and subsequent bone mineral density.

OBJECTIVE: To investigate the association of breastfeeding during adolescence with bone mineral density (BMD) during young adulthood. METHODS: Secondary analysis of data from the National Health and Nutrition Examination Survey III, a nationally representative cross-sectional survey conducted from 1988 through 1994, was performed. The BMDs for 5 regions of the proximal femur as measured by dual energy x-ray absorptiometry were compared for 5 groups of women aged 20 to 25 years (n = 819); the groups included those who had been: (1) adolescent mothers and had breastfed (n = 94), (2) adolescent mothers and had not breastfed (n = 151), (3) mothers who first gave birth as adults and breastfed (n = 67), (4) mothers who first gave birth as adults and had not breastfed (n = 89), and (5) nulliparous (n = 418). SUDAAN software was used to account for the complex sampling design of the National Health and Nutrition Examination Survey. Adjusted mean differences in BMD were estimated using least-squares linear regression. RESULTS: During young adulthood, women who breastfed during adolescence had higher adjusted BMDs, which was statistically significant in 4 of the 5 regions, than those who had not breastfed (total proximal femur area difference, 0.049 gm/cm(2) [95% confidence interval, 0.002-0.095]) and BMDs equivalent to nulliparous women (total proximal femur area difference, 0.024 gm/cm(2) [95% confidence interval, -0.023 to 0.071]). Adjusting also for obstetric variables, women who breastfed during adolescence had higher BMDs in all 5 regions compared with their peers who had not breastfed (total proximal femur area difference, 0.053 gm/cm(2) [95% confidence interval, 0.029-0.077]). CONCLUSIONS: In this nationally representative sample, breastfeeding by adolescent mothers was associated with greater BMD in the proximal femur during young adulthood. Lactation was not found to be detrimental and may be protective to the bone health of adolescent mothers.

Absorptiometry, Photon↗
PubMed2001

[Effect of design in cluster sampling to estimate the distribution of occupations among workers].

OBJECTIVE: To describe the effect of design associated with a sample survey carried out to estimate the distribution of occupations within an economic active population. METHODS: A cluster sample of households, chosen from a comprehensive directory via systematic random sampling, was performed including 4,782 of all residences in Botucatu, Brazil, between June and July 1997. RESULTS: Of the 4,782 households, 17,219 subjects were assessed. Due to the loss of distribution heterogeneity of the occupations within the households, the effect of design found ranged from 1.00 to 1.96. CONCLUSIONS: The results suggest that when planning similar studies aiming at estimating the distribution of occupations among economic active populations, the effect of design should be estimated as e=1.50 for surveys in urban areas, and e=2.00 for surveys in rural areas.

Cluster Analysis↗
PubMed2005

Association between psychiatric disorders and smoking stages among Latino adolescents.

OBJECTIVE: We examined the prevalence of smoking behaviors and their association with psychiatric disorders within a representative sample of youth from Puerto Rico. METHOD: A complex sampling design was used and analyses were conducted to account for the unequal selection probability, stratification and clustering. All analyses were weighted back to the population from which they were drawn. Psychiatric and substance use disorders were assessed using the parent and youth versions of the Diagnostic Interview Schedule for Children, Version 4.0 (DISC-IV). RESULTS: After controlling for other comorbidity, major depression and oppositional defiant disorder were significantly associated with nicotine dependence, rather than with lower levels of use. In contrast, conduct disorder was generally associated with lower levels of use rather than with nicotine dependence. As expected, the alcohol and drug use disorders demonstrated some of the strongest associations with individual smoking stages. CONCLUSIONS: By examining psychiatric correlates of smoking stages within an island-wide sample of adolescents, the present study highlights those disorders that may play a role in the development and/or persistence of smoking behavior in Puerto Rico and further clarifies the appropriate targets for smoking intervention conducted in community settings.

Adolescent↗
PubMed2006

In-patient detoxification procedures, treatment retention, and post-treatment opiate use: comparison of lofexidine + naloxone, lofexidine + placebo, and methadone.

OBJECTIVE: In-treatment and post-treatment outcomes were compared for three detoxification procedures (lofexidine+naloxone, lofexidine+placebo naloxone, and methadone). SAMPLE AND DESIGN: The sample was 137 opiate dependent in-patients. Detoxification treatments were 6-day lofexidine+naloxone (n=45), lofexidine+placebo naloxone (n=46), or 10-day methadone reduction (n=46). A cohort study design was used with double-blind random allocation to lofexidine+naloxone versus lofexidine+placebo. Patients who did not consent to, or who were excluded from randomisation received methadone. RESULTS: Outcome differences between treatment groups at follow-up were generally associated with length of stay post-detoxification rather than detoxification procedure. Among patients who were not opiate abstinent throughout follow-up (n=85), those who received lofexidine+naloxone detoxification reported a longer interval to first heroin use, with an interaction between detoxification medication and subsequent retention in treatment also identified. CONCLUSIONS: Detoxification medication may influence medium-term opiate use outcomes via its effect upon retention in treatment.

Adolescent↗
PubMedDate not supplied

Suramin in combination with 5-fluorouracil (5-FU) and leucovorin (LV) in metastatic colorectal cancer patients resistant to 5-FU+LV-based chemotherapy.

AIMS AND BACKGROUND: Suramin has been shown to be of interest as a potential new anticancer agent because of its capacity to inhibit the binding of several growth factors to their receptors and to inhibit the growth of cancer cells in vitro. Since multi-autocrine loops involving growth factors which are antagonized by suramin have been demonstrated in colorectal cancer, we previously evaluated the activity of suramin in patients with advanced colorectal cancer. Interestingly, in this study three patients who had received 5-FU+LV after suramin, although heavily pretreated with fluoropyrimidines, obtained an objective response. This observation was intriguing as it might have been that suramin had changed the biology of the tumor, making it sensitive to 5-FU+LV. We therefore conducted the present study to investigate the possibility that suramin might overcome the resistance to 5-FU+LV. METHODS AND STUDY DESIGN: Only colorectal cancer patients with metastatic and progressive disease during 5-FU+LV-based chemotherapy were eligible for this study. Suramin was administered for eight weeks at doses determined by means of a computer-assisted dosing algorithm that used Bayesian pharmacokinetics to maintain suramin plasma concentrations of 200-250 microg/ml. 5-FU was administered weekly at a dosis of 450 mg/m2 halfway through a two-hour infusion of I-LV 250 mg/m2 starting one week after the initiation of suramin for a maximum of 26 weeks. RESULTS: Treatment was relatively well tolerated, but no objective responses were observed after the accrual of 13 patients in the first stage of the trial. Consequently, the trial was interrupted according to the initial two-stage sampling design. CONCLUSIONS: The present study does not support the hypothesis that suramin might overcome resistance to 5-FU+LV and its use in colorectal cancer is not recommended.

Aged↗
PubMed2003

Reminder letter, tailored stepped-care, and self-choice comparison for repeat mammography.

BACKGROUND: The main benefits of mammography come from regular on-schedule screening. However, few studies have examined interventions to achieve repeat screening. SETTING AND PARTICIPANTS: Participants were women aged 50 to 74, recruited through one setting in Rhode Island and another in North Carolina. Participants had a mammogram already scheduled at recruitment, and had to keep that appointment in order to be eligible for the repeat mammography intervention. A total of 1614 women were in the intervention sample. DESIGN: A four-group randomized design was used: Group 1, a simple reminder letter; Group 2, a 2-month, tailored, stepped intervention delivered 2 months after the completed mammogram; Group 3, a 10-month, tailored, stepped intervention delivered 2 months before the repeat mammogram was due; and Group 4, self-choice of one of the above three strategies. INTERVENTION: The intervention took place between June 1996 and May 1997. The reminder letter and two levels of the stepped intervention were delivered by mail. The third level of the stepped strategy was a counselor telephone call. Groups 2 and 3 were identical, except for timing. OUTCOME MEASURE: Obtaining the next due mammogram within 15 months, based on clinic records. RESULTS: There were no statistically significant differences among the four groups, both in the total sample and at the two sites separately. CONCLUSIONS: On average, a simple reminder may be as effective as more complex strategies for women with a prior on-schedule exam. However, attention is still needed to identify women at risk of lapsing from screening. Some women may require more-intensive interventions.

Aged↗
PubMed2000

Clinical drug trials: practical problems of phase III.

INTRODUCTION: Phase III randomised clinical trials provide the highest level of evidence to support the superior effectiveness of a new drug or therapy. The main practical problems encountered in the initiation, design, conduct and completion of both investigator-initiated and sponsor-initiated phase III clinical drug trials will be reviewed. METHODS: A Medline search of clinical drug trials conducted in Singapore as well as journal articles highlighting important methodological considerations and practical problems encountered in phase III clinical trials was performed. RESULTS: Several phase III randomised clinical trials have been conducted in Singapore which include the investigation of interventions that include tramadol, estradiol patch and colloidal bismuth subcitrate. The main problems encountered in phase III clinical drug trials include difficulties with recruitment of subjects for the study, proper filing of case report forms, special problems in children and the elderly, adequate compensation for adverse events and the adequate archival of documents of the completion of trials. In investigator-initiated trials, careful attention should be given to identifying a suitable study question, choice of study design, sample size calculations and data analysis. In sponsor-initiated trials, a good working relationship with the sponsor is essential and publication terms should be spelt from the onset of the trial. CONCLUSIONS: Well-planned clinical trials led by a team of competent investigators are essential for the conduct of rigorous sponsor-initiated and investigator-initiated clinical trials.

Clinical Trials, Phase III as Topic↗
PubMedDate not supplied

[Occupational exposure to antineoplastic drugs in a hospital setting: biological and environmental monitoring].

OBJECTIVE: To estimate the occupational exposure of hospital personnel handling antineoplastics drugs using a highly sensitive and specific analitycal method in biological and environmental samples. DESIGN: To develop analitycal methods for the biological and environmental monitoring of more than one substance. SETTING: Five departments of the Policlinico Sant'Orsola-Malpighi (Bologna, Italy) involved in the preparation and administration of antineoplastic drugs. PARTICIPANTS: 50 nurses handling antineoplastics drugs. MAIN OUTCOME MEASURES: Evaluation of the occupational exposure of hospital personnel handling and administering anticancer drug cocktails. RESULTS: 19 of 50 subjects were positive to biological monitoring. Three were positive for MTX only, 11 for CP only and 5 subjects were positive for both. Urinary MTX levels ranged from 0.3 to 2.0 ppb, CP ranged fom 0.06 to 10.0 ppb. Wipe tests showed a higher contamination on the hoods working tray (where drugs are prepared), suggesting that the organization layout can affect the surface contamination level. Samples from each department resulted positive for at least one of three drugs. CONCLUSIONS: The analytical methods developed allow sensitive and specific determination of indicators of internal and external dose. Biological monitoring is of primary importance for assessing the real espoxure of hospital personnel during the preparation and administration of the drugs. Environmental monitoring stresses the importance to observe the Guidelines for standard operating procedures and the importance of protective disposables to reduce exposure and the associated health risk.

Antineoplastic Agents↗
PubMed2005

Population plasma pharmacokinetics of 11C-flumazenil at tracer concentrations.

OBJECTIVE: The objectives of the study were to develop a population pharmacokinetic model for (11)C-flumazenil at tracer concentrations, to assess the effects of patient-related covariates and to derive an optimal sampling protocol for clinical use. METHODS: A population pharmacokinetic model was developed using nonlinear mixed effects modelling (NONMEM) with data obtained from 51 patients with either depression or epilepsy. Each patient received approximately 370 MBq (1-4 microg) of (11)C-flumazenil. The effects of selected covariates (gender, weight, type of disease and age) were investigated. The model was validated using a bootstrap method. Finally, an optimal sampling design was established. RESULTS: The population pharmacokinetics of tracer quantities of (11)C-flumazenil were best described by a two compartment model. Type of disease and weight were identified as significant covariates (P < 0.002). Mean population pharmacokinetic parameters (percent coefficient of variation) were: CL 1530 mL min(-1) (6.6%), V(1) 24.8 x 10(3) mL (3.8%), V(2) 27.3 x 10(3) mL (5.4%), and Q 2510 mL min(-1) (6.5%). CL was 20% lower in patients with epilepsy, and the influence of weight on V(1) was 0.55% kg(-1). For the prediction of the AUC, a combination of two time points at t = 30 and 60 min post injection was considered optimal (bias -0.7% (95% CI -2.2 to 0.8%), precision 5.7% (95% CI 4.5-6.9%)). The optimal sampling strategy was cross-validated (observed AUC = 296 MBql(-1) min(-1) (95% CI 102-490), predicted AUC = 288 MBql(-1) min(-1) (95% CI 70-506)). CONCLUSIONS: The population pharmacokinetics of tracer quantities of (11)C-flumazenil are well described by a two-compartment model. Inclusion of weight and type of disease as covariates significantly improved the model. Furthermore, an optimal sampling procedure may increase the feasibility and applicability of (11)C-flumazenil PET.

Adult↗
PubMed2002

Psychosocial risk factors for depressive disorders in late life.

This article summarizes research findings on psychosocial risk factors for late life depressive disorders. The article draws heavily on longitudinal cohort studies of well-defined, population-based samples with diagnostic measures that assess the risk of incident or new-onset depressive episodes. These studies have identified a number of significant psychosocial risk factors for late life depressive disorders, including life events and ongoing difficulties; death of a spouse or other loved one; medical illness and injuries; disability and functional decline; and lack of social contact. Additional evidence suggests that the impact of these psychosocial risk factors on depression can be enhanced or buffered by personal or environmental factors. Although many of these psychosocial risk factors are more prevalent among older than younger adults, it is not clear that their impact on the risk of depression differs by age. Methodological challenges to advancing research on psychosocial risk factors for late life depression are reviewed, including problems related to study designs, sample selection, and measurement.

Aged↗
PubMed2006

A descriptive study of youth risk behavior in urban and rural secondary school students in El Salvador.

BACKGROUND: Adolescence is an important stage of life for establishing healthy behaviors, attitudes, and lifestyles that contribute to current and future health. Health risk behavior is one indicator of health of young people that may serve both as a measure of health over time as well as a target for health policies and programs. This study examined the prevalence and distribution of youth health risk behaviors from five risk behavior domains-aggression, victimization, depression and suicidal ideation, substance use, and sexual behaviors-among public secondary school students in central El Salvador. METHODS: We employed a multi-stage sampling design in which school districts, schools, and classrooms were randomly selected. Data were collected using a self-administered questionnaire based on the United States Center for Disease Control and Prevention's Youth Risk Behavior Survey. Sixteen schools and 982 students aged 12-20 years participated in the study. RESULTS: Health risk behaviors with highest prevalence rates included: engagement in physical fight (32.1%); threatened/injured with a weapon (19.9%); feelings of sadness/hopelessness (32.2%); current cigarette use (13.6%); and no condom use at last sexual intercourse (69.1%). Urban and male students reported statistically significant higher prevalence of most youth risk behaviors; female students reported statistically significant higher prevalence of feelings of sadness/hopelessness (35.6%), suicidal ideation (17.9%) and, among the sexually experienced, forced sexual intercourse (20.6%). CONCLUSION: A high percentage of Salvadoran adolescents in this sample engaged in health risk behaviors, warranting enhanced adolescent health promotion strategies. Future health promotion efforts should target: the young age of sexual intercourse as well as low condom use among students, the higher prevalence of risk behaviors among urban students, and the important gender differences in risk behaviors, including the higher prevalence of reported feelings of sadness, suicidal ideation and forced sexual intercourse among females and higher sexual intercourse and substance use among males. Relevance of findings within the Salvadoran and the cross-national context and implications for health promotion efforts are discussed.

Journal Article↗
PubMed2000

Genetic epidemiologic studies on age-specified traits. NIA Aging and Genetic Epidemiology Working Group.

This commentary calls attention to the value of combining genetic and epidemiologic methods in studies to understand the determinants of two crucial aspects of aging: ages at which certain outcomes (e.g., disease, mortality) occur and rates of change with age of individual's characteristics (e.g., physiologic functions, disease risk factors). Inclusion of age in the specification of traits in genetic epidemiologic studies could lead to improved strategies to increase healthy life expectancy and evaluate individuals' risk for age-related morbidity. Special issues that make genetic epidemiologic approaches important for studies of age-specified phenomena as well as opportunities and challenges for such studies are discussed, including study designs, sampling frames, databases, analytic tools, and related methodological issues. This commentary is based on a report prepared by the Aging and Genetic Epidemiology Working Group, convened by the National Institute on Aging to review opportunities for research on the genetic epidemiology of aging-related outcomes. The report, which contains more extensive discussion, literature review, and references, is available on the World Wide Web at http://www.nih.gov/nia/conferences/GeneticReport111199.htm.

Age Factors↗