Biomedical subjects

Tzuo-Yun Lan

Publications and source records attributed to Tzuo-Yun Lan.

6 recordsLinked to original sources

PubMed2007

Areca nut chewing and mortality in an elderly cohort study.

Compared with the well-documented association with betel-related cancer, little is known about the long-term effect of areca nut chewing on other fatal diseases. The authors' analyses were based on a population-based cohort study in Taiwan, including 4,049 participants aged 60 years or older enrolled in 1989 and 2,462 participants aged 50-66 years enrolled in 1996. Information regarding betel quid chewing and covariates was collected at baseline and was updated at subsequent interviews. Proportional hazards analysis was performed to determine the effect of chewing on all-cause and cause-specific deaths. During a mean follow-up of 9.5 years, 2,309 deaths occurred. Ever chewers were at higher risk of only total (hazard ratio = 1.19, 95% confidence interval: 1.05, 1.35) and cerebrovascular (hazard ratio = 1.66, 95% confidence interval: 1.19, 2.30) deaths. Furthermore, increased chewing-years or quid-years appeared to be associated with increased mortality risk (linear trend: p = 0.02 for total mortality and p = 0.001 for cerebrovascular mortality). The authors found that, although betel quid chewing resulted in a statistically significant increase in the risk of total and cerebrovascular deaths in the elderly population, the associations were weak and should be interpreted with caution. Further studies are needed to confirm these findings and to better understand the possible mechanisms of death.

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PubMed2006

Relationship between components of leisure physical activity and mortality in Taiwanese older adults.

BACKGROUND: Whether the major components of leisure physical activity (number of types, intensity, frequency, and duration) have independent contribution to mortality reduction and there is a minimum amount of activity beneficial for the elderly remain unclear. METHODS: The prospective follow-up study aimed at examining the relationship between exercise components and total mortality in general elderly population. A total of 2113 persons aged 65 and older participating in 2001 Taiwan National Health Interview Survey were studied. Information regarding leisure physical activity, its energy parameters, other factors at baseline, and vital status at the end of 2003 was analyzed with Cox model. RESULTS: A total of 197 deaths occurred during a 2-year follow-up. Regular exercisers reduced 35% risk of death compared with sedentary individuals after adjustment for covariates. Moreover, exercisers with a weekly amount of energy exceeding 1000 kcal had significant benefit of risk reduction when energy expenditure is considered. There was a significant dose-response relationship between number of activity and the reduction in total mortality. The benefit on mortality reduction among the three components of total energy amount was only observed in intensity. CONCLUSIONS: For the amount of energy dedicated to leisure physical activity, older persons are recommended to expend at least 1000 kcal per week through regular exercise for mortality reduction. In addition to energy amount, protection of exercise against death also increases with the number of activities. Among the three components of total amount of energy, only intensity is significantly associated with mortality reduction.

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PubMed2004

Variation in thresholds for reporting mobility disability between national population subgroups and studies.

BACKGROUND: Disability questions require older people to report difficulties with everyday activities, using broad categorical responses. Relatively little is known about population group differences in the thresholds for reporting difficulty or inability with medium-distance mobility against tested mobility-related performance. We aimed to estimate the thresholds on tested performance at which self-reports change from one category to another, across a range of sociodemographic subgroups. We also aimed to compare reported and tested performance across two national population studies. METHODS: The samples were from the third U.S. National Health and Nutrition Examination Study (NHANES III) and the Longitudinal Aging Study Amsterdam (LASA). Measures of gait speed, chair stands, and peak expiratory flow rate in both studies yielded the validated index of mobility-related physical limitations (MOBLI). Latent probit models were used to estimate cutpoints (thresholds) on the index for reporting difficulty or inability to walk a medium distance. RESULTS: Thresholds for reporting difficulty or inability were studied by age, sex, race, educational level, and income in NHANES III. In models adjusting for the other factors, performance thresholds for reporting disability categories varied by age and income. The younger elderly persons in NHANES III on average reported difficulties or inabilities only when they reached a more severe level of tested limitation compared with older old persons. A similar pattern exists for those on higher incomes. For race, differences in threshold were present only for reporting inability, but not difficulty. Significant differences in thresholds were not present between groups defined by sex or for years of education. Comparisons between the NHANES and LASA studies show that lower reported mobility difficulty or inability prevalence in the Dutch sample is attributable both to reporting at higher levels of limitation and to better functioning. CONCLUSIONS: There is evidence of differences in thresholds for reporting mobility disability, especially across age and income groups in older Americans. Further work is needed to understand the perceptual, attitudinal, or environmental factors that cause these reporting differences.

Activities of Daily Living↗

PubMed2003

The predictive validity for mortality of the index of mobility-related limitation--results from the EPESE study.

BACKGROUND: self-reported disability reflects physical, environmental and attitudinal factors. We have previously reported the empirical identification of three simple tests to provide an index of (ambulatory) mobility-related physiological limitations (MOBLI). Evidence of the MOBLI 's responsiveness over time has been presented. Evidence of the predictive validity of the index is needed. OBJECTIVE: we aimed to measure the predictive validity for future mortality of the MOBLI and of self-reported mobility disability in a longitudinal cohort study. METHODS: data are from the sixth annual interview for two sites in the Established Populations for Epidemiologic Studies of the Elderly study. Included were 3,040 people, with information about self-reported walking difficulties, walking speed, time to complete five chair stands and peak expiratory flow. Age- and sex-adjusted death rates over a 4-year follow-up were computed, and proportional hazards regression models were used in the analysis. RESULTS: the MOBLI score is associated with subsequent mortality over 4 years, with evidence of a 'dose-response' relationship. The predictive value for mortality of the MOBLI score is similar to that of self-reported mobility disability in the studied population. CONCLUSIONS: the 'objective' MOBLI index has predictive validity as a continuous or dichotomised measure of the physiological component of mobility limitation in older populations. Given its empirical basis and face validity, predictive validity and responsiveness to change, MOBLI should be considered for local validation and use in epidemiological comparisons of older populations across countries or over longer periods of time.

Activities of Daily Living↗

PubMed2003

Responsiveness of the index of mobility limitation: comparison with gait speed alone in the longitudinal aging study amsterdam.

BACKGROUND: Interpreting self-reported disability differences between diverse older populations is complicated by differences in attitudes and environment. We have previously reported on the index of mobility-related limitation tests (MOBLI), and shown that it predicts mortality over 4 years. In this article, we examine whether the index is responsive to changes in self-reported mobility disability. METHODS: Data on gait speed, time to complete 5 chair stands, and peak expiratory flow rate, with self-reported difficulty walking for 5 minutes, were available from the baseline and two 3-year follow-ups in the Longitudinal Aging Study Amsterdam. Analysis used data on changes in the index (or walking speed alone) and corresponding change over 3 years in self-reported difficulty or inability with a medium-distance walk. RESULTS: During all follow-ups, groups reporting deterioration in functioning had relatively larger changes in gait speed and MOBLI score than did the "no deterioration" groups. In comparative analyses of responsiveness, the MOBLI score had a larger responsiveness index, higher odds ratios, and larger receiving operating characteristic area than gait speed alone. CONCLUSIONS: The MOBLI index of mobility-related physical limitation tests is responsive to changes in self-reported mobility disability over two 3-year periods, and performs better than gait speed alone. This property is strongly supportive of its validity for epidemiological comparison of older populations across countries or over longer periods of time.

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PubMed2002

Performance tests and disability: developing an objective index of mobility-related limitation in older populations.

BACKGROUND: Disability reflects physiological limitations, social and environmental barriers, and "sickness" behavior. Being able to measure these influences separately would greatly assist interpretation of disability comparisons over time or between populations. This study aimed to identify an index of mobility-related limitations composed of physiological measures that are most closely associated with reported mobility disability in elders. METHODS: Data from the Third National Health and Nutrition Examination Survey (NHANES III) were used. Participants aged 60 and older were included in this analysis. Participants included 6596 respondents who were interviewed in their homes, and 5724 (87%) of these attended a further examination. Domains of measurements included body measurements, bone densitometry, physical examination, spirometry, fundus photography, and physical performance measures. Multivariate models were developed on a random half subsample of the data and were validated on the other half. Receiver operating characteristic (ROC) areas and logit rank slopes were used to evaluate sets of measures. RESULTS: In weighted logistic regression models, six and five measures were significantly associated with difficulty and inability in walking a quarter of a mile, respectively. These mainly included measures of lower extremity and lung function. A relatively minimal loss of sensitivity and specificity occurred from using more economical models, employing a subset of the identified measures. CONCLUSIONS: Subsets of measures associated with reported mobility disability could provide objective indices of mobility-related limitation for comparing populations or long-term population health monitoring.

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