High-risk drinking by college students continues to pose a significant threat to public health. Despite increasing evidence of the contribution of community-level and campus-level environmental factors to high risk drinking, there have been few rigorous tests of interventions that focus on changing these interlinked environments. The Study to Prevent Alcohol Related Consequences (SPARC) assessed the efficacy of a comprehensive intervention using a community organizing approach to implement environmental strategies in and around college campuses. The goal of SPARC was to reduce high-risk drinking and alcohol-related consequences among college students.
Ten universities in North Carolina were randomized to an Intervention or Comparison condition. Each Intervention school was assigned a campus/community organizer. The organizer worked to form a campus-community coalition, which developed and implemented a strategic plan to use environmental strategies to reduce high-risk drinking and its consequences. The intervention was implemented over a period of 3 years. Primary outcome measures were assessed using a web-based survey of students. Measures of high-risk drinking included number of days alcohol was consumed, number of days of binge drinking, and greatest number of drinks consumed (all in the past 30 days); and number of days one gets drunk in a typical week. Measures of alcohol-related consequences included indices of moderate consequences due to one’s own drinking, severe consequences due to one’s own drinking, interpersonal consequences due to others’ drinking, and community consequences due to others’ drinking (all using a past 30-day timeframe). Measure of alcohol-related injuries included (1) experiencing alcohol-related injuries and (2) alcohol-related injuries caused to others.
We found significant decreases in the Intervention group compared to the Comparison group in severe consequences due to students’ own drinking and alcohol-related injuries caused to others. In secondary analyses, higher levels of implementation of the intervention were associated with reductions in interpersonal consequences due to others’ drinking and alcohol-related injuries caused to others.
A community organizing approach promoting implementation of environmental interventions can significantly affect high-risk drinking and its consequences among college students.
Cognitive impairment is common in older adults with diabetes, yet it is unclear to what extent cognitive function is associated with health literacy. We hypothesized that cognitive function, independent of education, is associated with health literacy.
The sample included 537 African American, American Indian, and White men and women 60 years or older. Measures of cognitive function included the Mini-Mental State Examination (MMSE), Verbal Fluency, Brief Attention, and Digit Span Backward tests. Health literacy was assessed using the S-TOFHLA.
Cognitive function was associated with health literacy, independent of education and other important confounders. Every unit increase in the MMSE, Digit Span Backward, Verbal Fluency or Brief Attention was associated with a 20% (p<.001), 34% (p<.001), 5% (p<.01), and 16% (p<.01) increase in the odds of having adequate health literacy, respectively.
These results suggest that cognitive function is associated with health literacy in older adults with diabetes. Because poor cognitive function may undermine health literacy, efforts to target older adults on improving health literacy should consider cognitive function as a risk factor.
cognition; health literacy; diabetes
Disease risk-associated single nucleotide polymorphisms (SNPs) identified from genome-wide association studies (GWAS) have the potential to be used for disease risk prediction. An important feature of these risk-associated SNPs is their weak individual effect but stronger cumulative effect on disease risk. To date, a stable summary estimate of the joint effect of genetic variants on disease risk prediction is not available. In this study, we propose to use the graded response model (GRM), which is based on the item response theory, for estimating the individual risk that is associated with a set of SNPs. We compare the GRM with a recently proposed risk prediction model called cumulative relative risk (CRR). Thirty-three prostate cancer risk-associated SNPs were originally discovered in GWAS by December 2009. These SNPs were used to evaluate the performance of GRM and CRR for predicting prostate cancer risk in three GWAS populations, including populations from Sweden, Johns Hopkins Hospital, and the National Cancer Institute Cancer Genetic Markers of Susceptibility study. Computational results show that the risk prediction estimates of GRM, compared to CRR, are less biased and more stable.
In previous work, we described the development of an 81-item video-animated tool for assessing mobility. In response to criticism levied during a pilot study of this tool, we sought to develop a new version built upon a flexible framework for designing and administering the instrument.
Rather than constructing a self-contained software application with a hard-coded instrument, we designed an XML schema capable of describing a variety of psychometric instruments. The new version of our video-animated assessment tool was then defined fully within the context of a compliant XML document. Two software applications—one built in Java, the other in Objective-C for the Apple iPad—were then built that could present the instrument described in the XML document and collect participants’ responses. Separating the instrument’s definition from the software application implementing it allowed for rapid iteration and easy, reliable definition of variations.
Defining instruments in a software-independent XML document simplifies the process of defining instruments and variations and allows a single instrument to be deployed on as many platforms as there are software applications capable of interpreting the instrument, thereby broadening the potential target audience for the instrument. Continued work will be done to further specify and refine this type of instrument specification with a focus on spurring adoption by researchers in gerontology and geriatric medicine.
Knowing a patient’s health literacy can help clinicians and researchers anticipate a patient’s ability to understand complex health regimens and deliver better patient-centered instructions and information. Poor health literacy has been linked with lower ability to function adequately in health care systems.
We evaluated and compared three measures of health literacy and performance among older patients with diabetes.
Cross-sectional study utilizing in-person interviews conducted in participants’ homes.
A tri-ethnic sample (n = 563) of African American, American Indian, and white older adults with diabetes from eight counties in south-central North Carolina.
Participants completed interviews and health literacy assessments using the Short-Form Test of Functional Health Literacy in Adults (S-TOFHLA), the Rapid Estimates of Adult Literacy in Medicine Short-Form (REALM-SF), or the Newest Vital Signs (NVS). Scores for reading comprehension and numeracy were calculated.
Over 90% completed the S-TOFHLA numeracy and approximately 85% completed the S-TOFHLA reading and REALM-SF. Only 73% completed the NVS. The correlation of S-TOFHLA total scores with REALM-SF and NVS were 0.48 and 0.54, respectively. Age, gender, ethnic, educational and income differences in health literacy emerged for several instruments, but the pattern of results across the instruments was highly variable.
A large segment of older adults is unable to complete short-form assessments of health literacy. Among those who were able to complete assessments, the REALM-SF and NVS performed comparably, but their relatively low convergence with the S-TOFHLA raises questions about instrument selection when studying health literacy of older adults.
health literacy; older adults; diabetes
To describe the network of collaboration among agencies that serve children with complex chronic conditions (CCC) and identify gaps in the network.
We surveyed representatives from agencies that serve children with CCC in Forsyth County, North Carolina about their agencies’ existing and desired collaborations with other agencies in the network. We used Social Network Analytical methods to describe gaps in the network. Mean out- and in-degree centrality (number of collaborative ties extending from or directed towards an agency) and density (ratio of extant ties to all possible ties) were measured.
In this network with 3,658 possible collaborative ties, care-coordination agencies and pediatric practices reported the highest existing collaborations with other agencies (out-degree centrality: 32 and 30 respectively). Pediatric practices reported strong ties with subspecialty clinics (density: 73%), but weak ties with family support services (density: 3%). Pediatric practices and subspecialty clinics (in-degree: 26) received the highest collaborative ties from other agencies. Support services and durable medical equipment companies reported low ties with other agencies (out-degree: 7 and 10 respectively). Nursing agencies reported the highest desired collaborations (out-degree: 18). Support services, pediatric practices and care-coordination programs had the highest in-degree centrality (7, 6 and 6 respectively) for desired collaborations. Nursing agencies and support services had the greatest gaps in collaboration.
Although collaboration exists among agencies serving children with CCC, there are many gaps in the network. Future studies should explore barriers and facilitators to inter-agency collaborations and whether increased collaboration in the network improves patient-level outcomes.
children; special needs; collaboration; health services research
This study assessed college students’ reports of tobacco screening and brief intervention by student health centers providers.
3800 students from eight universities in North Carolina participated.
Web-based survey of a stratified random sample of undergraduates.
53% reported ever visiting their student health center. Of those, 62% reported being screened for tobacco use. Logistic regression revealed screening was higher among females and smokers, compared to nonsmokers. Among students who were screened and who reported tobacco use, 50% reported being advised to quit or reduce use. Brief intervention was more likely among current daily smokers compared to current nondaily smokers, as well as at schools with higher smoking rates. Screening and brief intervention were more likely at schools with lower clinic caseloads.
Results highlight the need to encourage college health providers to screen every patient at every visit and to provide brief intervention for tobacco users.
Tobacco; Smoking; Cessation
Adults with type 2 diabetes mellitus often have limitations in mobility that increase with age. An intensive lifestyle intervention that produces weight loss and improves fitness could slow the loss of mobility in such patients.
We randomly assigned 5145 overweight or obese adults between the ages of 45 and 74 years with type 2 diabetes to either an intensive lifestyle intervention or a diabetes support-and-education program; 5016 participants contributed data. We used hidden Markov models to characterize disability states and mixed-effects ordinal logistic regression to estimate the probability of functional decline. The primary outcome was self-reported limitation in mobility, with annual assessments for 4 years.
At year 4, among 2514 adults in the lifestyle-intervention group, 517 (20.6%) had severe disability and 969 (38.5%) had good mobility; the numbers among 2502 participants in the support group were 656 (26.2%) and 798 (31.9%), respectively. The lifestyle-intervention group had a relative reduction of 48% in the risk of loss of mobility, as compared with the support group (odds ratio, 0.52; 95% confidence interval, 0.44 to 0.63; P<0.001). Both weight loss and improved fitness (as assessed on treadmill testing) were significant mediators of this effect (P<0.001 for both variables). Adverse events that were related to the lifestyle intervention included a slightly higher frequency of musculoskeletal symptoms at year 1.
Weight loss and improved fitness slowed the decline in mobility in overweight adults with type 2 diabetes. (Funded by the Department of Health and Human Services and others; ClinicalTrials.gov number, NCT00017953.)
The NAFKAM International CAM Questionnaire (I-CAM-Q) was designed to facilitate cross-study comparisons of CAM usage. This research presents the first empirical study of the I-CAM-Q’s performance.
Materials and Methods
Data were collected in two studies in a multi-ethnic (African American, American Indian, and white) population of older adults in the US. In 2010, 564 adults 60+ years were recruited. The I-CAM-Q was interviewer-administered. Data were compared to those collected in 2002 from a random sample of 701 Medicare recipients 65+ years. The 2002 survey included an extensive inventory of specific CAM therapies derived from local ethnographic research. Comparisons of the responses for 14 CAM modalities common to the two studies used logistic regression adjusted for demographics.
There were no significant differences between the 2002 and 2010 surveys in the proportions reporting 10 modalities, including use of chiropractors, homeopaths, acupuncturists, herbalists, spiritual healers, vitamins, minerals, homeopathic remedies, Qigong, visualization, and prayer for health. Significantly less use of physicians and more use of relaxation techniques were reported in 2010. Herb use and garlic, as a specific herb, were reported significantly less in 2010.
Overall, the I-CAM-Q obtained results similar to those produced by a population-specific questionnaire. Those differences observed appear to reflect differences in the studies’ inclusion criteria or secular trends in CAM. This study supports the intention of the I-CAM-Q to substitute for local and regional surveys in order to allow cross-study comparisons of CAM use. Further tests, preferably through contemporaneous data collection are needed in other populations.
Complementary Medicine; Alternative Medicine; Diabetes; Elderly; African American; American Indian
Investigate the importance of viewing belief systems about health maintenance holistically.
Qualitative (N=74) and quantitative data (N=95) were obtained from multi-ethnic rural-dwelling older adults with diabetes to characterize their Common Sense Models (CSMs) of diabetes.
There is a discrete number of CSMs held by older adults, each characterized by unique clusters of diabetes-related knowledge and beliefs. Individuals whose CSM was shaped by biomedical knowledge were better able to achieve glycemic control.
Viewing individuals’ health beliefs incrementally or in a piece-meal strategy may be less effective for health behavior change than focusing on beliefs holistically.
Diabetes; common sense model; health beliefs; glycemic control; health behavior change
Gibbs sampler has been used exclusively for compatible conditionals that converge to a unique invariant joint distribution. However, conditional models are not always compatible. In this paper, a Gibbs sampling-based approach — Gibbs ensemble —is proposed to search for a joint distribution that deviates least from a prescribed set of conditional distributions. The algorithm can be easily scalable such that it can handle large data sets of high dimensionality. Using simulated data, we show that the proposed approach provides joint distributions that are less discrepant from the incompatible conditionals than those obtained by other methods discussed in the literature. The ensemble approach is also applied to a data set regarding geno-polymorphism and response to chemotherapy in patients with metastatic colorectal
Gibbs sampler; Conditionally specified distribution; Linear programming; Ensemble method; Odds ratio
Although the importance of the context of task performance in the assessment of mobility in older adults is generally understood, there is little empirical evidence that demonstrates how sensitive older adults are to subtle changes in task demands. Thus, we developed a novel approach to examine this issue.
We collected item response data to 81 animated video clips, where various mobility-related tasks were modified in a systematic fashion to manipulate task difficulty.
The participants (N = 234), 166 women and 68 men, had an average age of 81.9 years and a variety of comorbidities. Histograms of item responses revealed dramatic and systematic effects on older adults’ self-reported ability when varying walking speed, use of a handrail during ascent and descent of stairs, walking at different speeds outdoors over uneven terrain, and carrying an object. For example, there was almost a threefold increase in reporting the inability to walk at the fast speed compared with the slow speed for a minute or less, and twice as many participants reported the inability to walk at the fast speed outdoors over uneven terrain compared with indoors.
The data provide clear evidence that varying the contextual features and demands of a simple task such as stair climbing has a significant impact on older adults’ self-reporting of ability related to mobility. More work is needed on the psychometric properties of such assessments and to determine if this methodology has conceptual and clinical relevance in studying mobility disability.
Mobility; Aging; Disability; Physical function
The medical and personal circumstances of older persons present challenges for designing and analyzing clinical research studies in which they participate. These challenges presented by elderly study samples are not unique but they are sufficiently distinctive to warrant deliberate and systematic attention. Their distinctiveness originates in the multifactorial etiologies of geriatric health syndromes and the multiple morbidities accruing with aging at the end of life. The objective of this article is to identify a set of statistical challenges arising in research with older persons that should be considered conjointly in the practice of clinical research and that should be addressed systematically in the training of biostatisticians intending to work with gerontologists, geriatricians, and older study participants. The statistical challenges include design and analytical strategies for multicomponent interventions, multiple outcomes, state transition models, floor and ceiling effects, missing data, and mixed methods. The methodological and pedagogical themes of this article will be integrated by a description of a proposed subdiscipline of “gerontologic biostatistics” and supported by the introduction of new set of statistical resources for researchers working in this area. These conceptual and methodological resources have been developed in the context of several collaborating Claude D. Pepper Older Americans Independence Centers.
clinical research; statistics; aging; study design
The late life disability instrument (LLDI) was developed to assess limitations in instrumental and management roles using a small and restricted sample. In this paper we examine the measurement properties of the LLDI using data from the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study.
LIFE-P participants, aged 70-89 years, were at elevated risk of disability. The 424 participants were enrolled at the Cooper Institute, Stanford University, University of Pittsburgh, and Wake Forest University. Physical activity and successful aging health education interventions were compared after 12-months of follow-up. Using factor analysis, we determined whether the LLDI's factor structure was comparable with that reported previously. We further examined how each item related to measured disability using item response theory (IRT).
The factor structure for the limitation domain within the LLDI in the LIFE-P study did not corroborate previous findings. However, the factor structure using the abbreviated version was supported. Social and personal role factors were identified. IRT analysis revealed that each item in the social role factor provided a similar level of information, whereas the items in the personal role factor tended to provide different levels of information.
Within the context of community-based clinical intervention research in aged populations, an abbreviated version of the LLDI performed better than the full 16-item version. In addition, the personal subscale would benefit from additional research using IRT.
The protocol of LIFE-P is consistent with the principles of the Declaration of Helsinki and is registered at http://www.ClinicalTrials.gov (registration # NCT00116194).
Existing self-report measures of mobility ignore important contextual features of movement and require respondents to make complex judgments about specific tasks. Thus, we describe the development and validation of a short form (sf) video-animated tool for assessing mobility, the Mobility Assessment Tool—MAT-sf.
This study involves cross-sectional and longitudinal analyses examining the measurement properties of the MAT-sf. The MAT-sf consists of 10 animated video clips that assess respondents’ level of proficiency in performing each task. The main outcome measures used for validation included the Pepper Assessment Tool for Disability (PAT-D), the Short Physical Performance Battery (SPPB), and 400-m walk test.
Participants (n = 234), 166 women and 68 men, had an average age of 81.9 years and a variety of comorbidities with 65.4% having high blood pressure. An average SPPB score of 8.6 (range 2–12) suggests that the study sample had evidence of compromised physical function but was quite heterogeneous. The MAT-sf had good content validity, excellent test–retest reliability (r = .93), and criterion-related validity with the PAT-D. Moreover, the MAT-sf added considerable variance to the prediction of both SPPB scores and 400-m gait speed over and above the PAT-D mobility subscale. The MAT-sf also discriminated between older adults who completed or failed the 400-m walk test.
The MAT-sf is an innovative psychometrically sound measure of mobility. It has utility in epidemiological studies, translational science, and clinical practice.
Mobility; Aging; Measurement; Disability
Under-age drinking is a long-standing public health problem in the USA and the identification of underage drinkers suffering alcohol-related problems has been difficult by using diagnostic criteria that were developed in adult populations. For this reason, it is important to characterize patterns of drinking in adolescents that are associated with alcohol-related problems. Latent class analysis is a statistical technique for explaining heterogeneity in individual response patterns in terms of a smaller number of classes. However, the latent class analysis assumption of local independence may not be appropriate when examining behavioural profiles and could have implications for statistical inference. In addition, if covariates are included in the model, non-differential measurement is also assumed. We propose a flexible set of models for local dependence and differential measurement that use easily interpretable odds ratio parameterizations while simultaneously fitting a marginal regression model for the latent class prevalences. Estimation is based on solving a set of second-order estimating equations. This approach requires only specification of the first two moments and allows for the choice of simple ‘working’ covariance structures. The method is illustrated by using data from a large-scale survey of under-age drinking. This new approach indicates the effectiveness of introducing local dependence and differential measurement into latent class models for selecting substantively interpretable models over more complex models that are deemed empirically superior.
Differential measurement; Latent class; Local dependence; Marginal regression; Odds ratio; Second-order estimating equations
Relationships between non-use of highly active anti-retroviral therapy (HAART), race/ethnicity, violence, drug use and other risk factors are investigated using qualitative profiles of five risk factors (unprotected sex, multiple male partners, heavy drinking, crack, cocaine or heroin use, and exposure to physical violence) and association of the profiles and race/ethnicity with non-use of HAART over time.
A Hidden Markov Model (HMM) was used to summarize risk factor profiles and changes in profiles over time in a longitudinal sample of HIV-infected women enrolled in the Women's Interagency HIV Study (WIHS) with follow-up from 2002 to 2005 (N=802).
Four risk factor profiles corresponding to four distinct latent states were identified from the five risk factors. Trajectory analysis indicated that states characterized by high probabilities of all risk factors or by low probabilities of all risk factors were both relatively stable over time. Being in the highest risk state did not significantly elevate the odds of HAART non-use (OR: 1.05; 95% CI: 0.6-1.8). However, being in a latent state characterized by elevated probabilities of heavy drinking and exposure to physical violence, along with slight elevations in three other risk factors, significantly increased odds of HAART non-use (OR: 1.4; 95% CI: 1.1-1.9).
The research suggests that HAART use might be improved by interventions aimed at women who are heavy drinkers with recent exposure to physical violence and evidence of other risk factors. More research about the relationship between clustering and patterns of risk factors and use of HAART is needed.