Predictors of retention among African American and Hispanic older adult research participants in the Well Elderly 2 randomized controlled trial.

The purpose of this study was to document predictors of long-term retention among minority participants in the Well Elderly 2 Study, a randomized controlled trial of a lifestyle intervention for community-dwelling older adults. The primary sample included 149 African American and 92 Hispanic men and women aged 60 to 95 years, recruited at senior activity centers and senior residences. Chi-square and logistic regression procedures were undertaken to examine study-based, psychosocial and health-related predictors of retention at 18 months following study entry. For both African Americans and Hispanics, intervention adherence was the strongest predictor. Retention was also related to high active coping and average (vs. high or low) levels of activity participation among African Americans and high social network strength among Hispanics. The results suggest that improved knowledge of the predictors of retention among minority elders can spawn new retention strategies that can be applied at individual, subgroup, and sample-wide levels.

Intensive, progressive exercise improves quality of life following lumbar microdiskectomy: a randomized controlled trial.

OBJECTIVE: The purpose of the study was to examine changes in quality of life measures in patients who have undergone an intensive exercise program following a single level microdiskectomy. DESIGN: Randomized controlled trial with blinded examiners. SETTING: The study was conducted in outpatient physical therapy clinics. SUBJECTS: Ninety-eight participants (53 male, 45 female) who had undergone a single-level lumbar microdiskectomy allocated to receive exercise and education or education only. INTERVENTIONS: A 12-week periodized exercise program of lumbar extensor strength and endurance training, and mat and upright therapeutic exercises was administered. OUTCOME MEASURES: Quality of life was tested with the Short Form 36 (SF-36). Measurements were taken 4-6 weeks postsurgery and following completion of the 12-week intervention program. Since some participants selected physical therapy apart from the study, analyses were performed for both an as-randomized (two-group) design and an as-treated (three-group) design. RESULTS: In the two-group analyses, exercise and education resulted in a greater increase in SF-36 scales, role physical (17.8 vs. 12.1) and bodily pain (13.4 vs. 8.4), and the physical component summary (13.2 vs. 8.9). In the three-group analyses, post-hoc comparisons showed exercise and education resulted in a greater increase in the SF-36 scales, physical function (10.4 vs. 5.6) and bodily pain (13.7 vs. 8.2), and the physical component summary (13.7 vs. 8.9) when compared with usual physical therapy. CONCLUSIONS: An intensive, progressive exercise program combined with education increases quality of life in patients who have recently undergone lumbar microdiskectomy.

Does exercise tolerance testing at 60 days poststroke predict rehabilitation performance?

OBJECTIVE: To assess the relationship between exercise tolerance test (ETT) performance at 6 weeks poststroke and subsequent performance in a treadmill and overground locomotor training program (LTP). DESIGN: Prospective cohort study. SETTING: Exercise testing laboratory in either a primary care hospital or outpatient clinic. PARTICIPANTS: Community-dwelling individuals (N=469), 54.9±19.0 days poststroke, enrolled in the Locomotor Experience Applied Post-Stroke randomized controlled trial. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: For participants randomly assigned to LTP, the number of sessions needed to attain the training goal of 20 minutes of treadmill stepping was determined. Regression analyses determined the contribution of ETT performance (cycling duration), age, and 6-minute walk test (6MWT) distance to attainment of the stepping duration goal. RESULTS: Age, 6MWT, and ETT performance individually accounted for 10.74%, 10.82%, and 10.76%, respectively, of the variance in the number of sessions needed to attain 20 minutes of stepping. When age and 6MWT were included in the model, the additional contribution of ETT performance was rendered nonsignificant (P=.150). CONCLUSIONS: To the extent that ETT performance can be viewed as a measure of cardiovascular fitness rather than neurologic impairment, cardiovascular fitness at the time of the ETT did not make a significant unique contribution to the number of sessions needed to achieve 20 minutes of stepping. The 6MWT, which involves less intensive exercise than the ETT and therefore is likely to be predominantly affected by neurologic impairment and muscular condition, appeared to account for as much variance as the ETT.

Avoid lost discoveries, because of violations of standard assumptions, by using modern robust statistical methods.

OBJECTIVES: Recently, there have been major advances in statistical techniques for assessing central tendency and measures of association. The practical utility of modern methods has been documented extensively in the statistics literature, but they remain underused and relatively unknown in clinical trials. Our objective was to address this issue. STUDY DESIGN AND PURPOSE: The first purpose was to review common problems associated with standard methodologies (low power, lack of control over type I errors, and incorrect assessments of the strength of the association). The second purpose was to summarize some modern methods that can be used to circumvent such problems. The third purpose was to illustrate the practical utility of modern robust methods using data from the Well Elderly 2 randomized controlled trial. RESULTS: In multiple instances, robust methods uncovered differences among groups and associations among variables that were not detected by classic techniques. In particular, the results demonstrated that details of the nature and strength of the association were sometimes overlooked when using ordinary least squares regression and Pearson correlation. CONCLUSION: Modern robust methods can make a practical difference in detecting and describing differences between groups and associations between variables. Such procedures should be applied more frequently when analyzing trial-based data.

High blood pressure in Chinese ethnic minorities: report from rural Yunnan province.

BACKGROUND: Hypertension (HTN) is a growing cause of morbidity and mortality among rural Chinese. While HTN has been studied in various regions of China, little is known about HTN among ethnic minorities in rural China. METHODS: A total of 36 villages were randomly selected from Yunnan province, China. From these villages, a total of 1,676 subjects from 10 ethnic minorities and the Han ethnic majority were selected for interview and blood pressure (BP) measurement. From each village, 50-80 men and women between the ages of 50 and 70 years were randomly selected. HTN prevalence, treatment, and control rates of HTN were evaluated in these 11 ethnic groups. RESULTS: After controlling for age, gender, body mass index (BMI), smoking, alcohol, and monosodium glutamate intake, prevalence of HTN varied between 25% in the Hani minority and 64% in the Tibetan minority (P < 0.001). Treatment rates varied between 0% in the Hani minority and 41% in the Tibetan minority (P = 0.006). Control rates varied between 0% in the Hani minority and 17% in the Tibetan minority (P = 0.28). Prevalence, treatment, and control rates in the Han ethnic group were 35, 22, and 12%, respectively. CONCLUSIONS: The prevalence of HTN varies widely among China's ethnic groups. Treatment and control rates of HTN also vary and are inadequate in the minority ethnic groups as well as in the Han majority.

Whole-body and muscle protein metabolism are not affected by acute deviations from habitual protein intake in older men: the Hormonal Regulators of Muscle and Metabolism in Aging (HORMA) Study.

BACKGROUND: Acute deviations in protein intake before the quantification of protein kinetics in older humans may explain the controversy over the effects of older age on muscle protein synthesis and proteolysis rates. OBJECTIVE: We hypothesized that an acute decrease in protein intake from the habitual intake is associated with lower muscle protein synthesis and higher proteolysis rates, whereas an acute increase in protein intake from the habitual intake is associated with higher muscle protein synthesis and lower proteolysis rates. DESIGN: In 112 community-dwelling healthy men aged 65-90 y, we quantified resting whole-body [1,2-(13)C(2)]leucine kinetics, muscle mixed protein fractional synthesis rates (FSRs), and muscle proteasome proteolytic enzyme activities after participants consumed for 3 d controlled research meals (0.9-1.1 g protein · kg(-1) · d(-1)) that contained more or less protein than that habitually consumed and that induced alterations in nitrogen balance. RESULTS: Protein kinetic parameters were not significantly different between the groups, despite controlled research protein intakes that were lower (-0.2 to -0.3 g · kg(-1) · d(-1)) or higher (+0.2 g · kg(-1) · d(-1)) than habitual intakes and that induced negative (-22 to -25 mg · kg(-1) · d(-1)) or positive (22-25 mg · kg(-1) · d(-1)) nitrogen balance. Within these acutely altered protein intake and nitrogen balance boundaries, a reduction in protein intake from habitual intake and induction of negative nitrogen balance were not associated with higher proteolysis or lower muscle FSR, and an acute increase in protein intake from habitual intake and induction of positive nitrogen balance were not associated with lower proteolysis or higher muscle FSR. A higher quantitative insulin sensitivity check index was associated with lower whole-body proteolysis rates. CONCLUSIONS: The practice of acutely controlling protein intake, even at intakes lower than habitual intakes that induce negative nitrogen balance, before quantifying human protein kinetics does not significantly reduce muscle protein synthesis or increase proteolysis. Factors other than protein intake explain lower muscle protein synthesis rates with advanced age. This trial is registered at clinicaltrials.gov as NCT00183040.

An intensive, progressive exercise program reduces disability and improves functional performance in patients after single-level lumbar microdiskectomy.

BACKGROUND: Restoration of physical function following lumbar microdiskectomy may be influenced by the postoperative care provided. OBJECTIVE: The purpose of this study was to examine the effectiveness of a new interventional protocol to improve functional performance in patients who have undergone a single-level lumbar microdiskectomy. SETTING: The study was conducted in physical therapy outpatient clinics. DESIGN AND PARTICIPANTS: Ninety-eight participants (53 male, 45 female) who had undergone a single-level lumbar microdiskectomy were randomly allocated to receive education only or exercise and education. INTERVENTION AND MEASUREMENTS: The exercise intervention consisted of a 12-week periodized program of back extensor strength (force-generating capacity) and endurance training and mat and upright therapeutic exercises. The Oswestry Disability Index (ODI) and physical measures of functional performance were tested 4 to 6 weeks postsurgery and 12 weeks later, following completion of the intervention program. Because some participants sought physical therapy outside of the study, postintervention scores were analyzed for both an as-randomized (2-group) design and an as-treated (3-group) design. RESULTS: In the 2-group analyses, exercise and education resulted in a greater reduction in ODI scores and a greater improvement in distance walked. In the 3-group analyses, post hoc comparisons showed a significantly greater reduction in ODI scores following exercise and education compared with the education-only and usual physical therapy groups. LIMITATIONS: The limitations of this study include a lack of adherence to group assignment, disproportionate therapist contact time among treatment groups, and multiple use of univariate analyses. CONCLUSIONS: An intensive, progressive exercise program combined with education reduces disability and improves function in patients who have undergone a single-level lumbar microdiskectomy.

The influence of depressive symptoms on experimental smoking and intention to smoke in a diverse youth sample.

Numerous studies have shown associations between smoking and depression, but the generalizability of the relationship across ethnic groups remains unknown. The present study assessed the association between depression and smoking intention and experimentation among adolescents from four ethnic groups in the Los Angeles area-Chinese/Chinese American, Latino/Hispanic, Persian/Iranian, and White. Over 800 7th graders in the Los Angeles area completed measures of depressive symptoms, experimentation with smoking, intention to smoke, and sociodemographic covariates. Chinese/Chinese American students had the lowest levels of depressive symptoms, whereas Latinos/Hispanics had the highest levels. Latinos/Hispanics also were the most likely to intend to smoke in the next year and were the most likely to have started experimenting with cigarette smoking. Depressive symptoms were significantly associated with intention to smoke even after controlling for language use acculturation, socioeconomic status, gender, and ethnicity. The association between depressive symptoms and intention to smoke did not vary significantly across ethnic groups. These results indicate that the association between depressive symptoms and adolescent smoking generalizes across diverse ethnic groups.

How can statistical approaches enhance transdisciplinary study of drug misuse prevention?

Application of statistical techniques in transdisciplinary research includes statistical model selection and model specification. This paper presents statistical models used in drug misuse prevention research. The historical roots of these models are discussed to illustrate the numerous disciplines from which different techniques originated. Single and multilevel approaches are described to illustrate methods of synthesizing perspectives from different scientific arenas. Using single-level approaches in transdisciplinary research, these models can easily incorporate broader theoretical considerations and more integrated hypotheses by representing each discipline with a set of variables. Simultaneous testing of every set of variables obtained from different disciplines may provide more comparable results to identify critical factors associated with substance-use behavior. Using multilevel approaches, more powerful syntheses across disciplines can be achieved by representing each discipline at a different level.

Using focus groups to develop a culturally sensitive methodology for epidemiological surveys in a Latino population: findings from the Los Angeles Latino Eye Study (LALES).

BACKGROUND: Many standardized survey instruments are initially developed in English-speaking populations. These instruments may not be culturally appropriate for other ethnic groups, such as Latinos. METHODS: The Los Angeles Latino Eye Study (LALES) was designed to determine the prevalence of blindness, visual impairment, and ocular diseases; risk factors for these diseases; and general and ocular healthcare use among non-institutionalized adult Latinos in suburban Los Angeles County, California. The LALES investigators used focus groups to develop questionnaires and to devise culturally sensitive methods for implementing this epidemiologic study in a Latino population. Eighty-four respondents were administered the in-home questionnaire and then scheduled into one of 6 in-home focus groups, allowing participants to reflect in groups about the study, their participation, and the state of the instruments and the translations. FINDINGS: Overall, respondents reported that the questionnaire was well written, easy to understand, and very clear. Recommendations from participants included: 1) keep questions brief; 2) minimize the number of response choices; 3) keep phrasing clear; 4) simplify technical terms; 5) provide test results immediately after the clinical examination; and 6) hire Spanish-speaking staff to increase participants' trust and confidence. CONCLUSION: Focus groups assisted in yielding a culturally appropriate survey research tool and methodology for this population-based study in a Latino community.