Epidemiology of multiple childhood traumatic events: child abuse, parental psychopathology, and other family-level stressors.

BACKGROUND: Multiple family-level childhood stressors are common and are correlated. It is unknown if clusters of commonly co-occurring stressors are identifiable. The study was designed to explore family-level stressor clustering in the general population, to estimate the prevalence of exposure classes, and to examine the correlation of sociodemographic characteristics with class prevalence. METHOD: Data were collected from an epidemiological sample and analyzed using latent class regression. RESULTS: A six-class solution was identified. Classes were characterized by low risk (prevalence=23%), universal high risk (7 %), family conflict (11 %), household substance problems (22 %), non-nuclear family structure (24 %), parent's mental illness (13 %). CONCLUSIONS: Class prevalence varied with race and welfare status, not gender. Interventions for childhood stressors are person-focused; the analytic approach may uniquely inform resource allocation.

Widespread musculoskeletal pain and the progression of disability in older disabled women.

BACKGROUND: Widespread musculoskeletal pain is a poorly understood but common problem in older adults. Little is known about the progression of disability related to this condition. OBJECTIVE: To determine whether widespread musculoskeletal pain increases the risk for worsening disability in older women with disabilities. DESIGN: Prospective cohort study. SETTING: The Women's Health and Aging Study. PARTICIPANTS: 1002 community-dwelling women 65 years of age or older with disability. MEASUREMENTS: Widespread musculoskeletal pain was defined as pain in the upper and lower extremities and axial pain with moderate or severe pain in at least one of the three regions. Worsening disability was defined as progression from no or mild difficulty to severe difficulty or inability to perform activities of daily living (ADLs), walk one-quarter mile, or lift 10 lbs. RESULTS: At baseline, 24% of participants had widespread pain and 25% had no pain or only mild pain in a single site. Women with widespread pain were 2.5 to 3.5 times more likely to have severe difficulty with ADLs, walking, or lifting at baseline compared with women who had no or mild pain. In women without severe difficulty initially, widespread pain nearly doubled the risk for progression to severe difficulty in each of the tasks, after adjustment for age, body mass index, comorbid illness, and other confounders. CONCLUSION: Widespread musculoskeletal pain is frequent among community-dwelling older women with disability and appears to predict the progression of disability. Efforts to better understand the cause of this pain and its treatment might reduce the overall burden of disability.

Designing a community study of moderately to severely disabled older women: the Women's Health and Aging Study.

PURPOSE: This paper reports on the design of a community-based study focusing on the effects of prevalent and incident disease and other modifying influences, on changes in functioning among moderately and severely disabled elderly women over a 3-year period [the Women's Health and Aging Study (WHAS)]. METHODS: An approach to conceptualizing and assessing disability which captured functional difficulty across a broad range of activities and tasks was developed, tested on existing national data, and used, in the form of a brief screening instrument, to identify moderately to severely disabled elderly women in a large community sample representative of women 65 and older. Women meeting study criteria were recruited for a baseline interview, a 3-hour in-home clinical exam, as well as follow-up interviews and physical performance tests at 6-month intervals for three years. RESULTS: Prevalence of moderate to severe disability among the screened population proved similar to that expected from analysis of national data (about one-third). The screening interview response rate was 78%, and 71% of women eligible by disability criteria participated. Only women completing both the baseline interview and clinical exam were counted as respondents. Analysis of characteristics of participants and nonparticipants indicated no selection bias related to levels of disability. However, education, race, and age were associated with participation. Women with some college education, black women, and younger women were more likely to participate. CONCLUSIONS: The approach used to identify and recruit moderately to severely disabled elderly women in the WHAS is both feasible and applicable to other community-based research where inclusion of elderly people with moderate to severe disability across several areas of functioning is an objective. Other aspects of study design, such as use of proxy respondents, will also affect recruitment of individuals with impaired functioning into epidemiologic studies.

Premorbid prevalence of ADHD and development of secondary ADHD after closed head injury.

OBJECTIVE: To determine premorbid prevalence of attention-deficit hyperactivity disorder (ADHD) in children with moderate and severe closed head injury (CHI), to determine incidence of ADHD 1 year after injury, and to characterize children who develop ADHD by demographic, neuropsychiatric, and outcome variables. METHOD: Ninety-nine children who had severe and moderate CHI were followed up for 1 year. Premorbid and 1-year postinjury psychiatric status were ascertained by parent and child structured interviews and questionnaires measuring affective lability, aggression, apathy, and social judgment. RESULTS: Premorbid prevalence of ADHD was 0.20, significantly higher than in a reference population (0.045). Fifteen of the remaining 80 children (0.19) developed full ADHD criteria (except for age of onset) by the end of the first year. Children who developed secondary ADHD (S-ADHD) had significantly greater premorbid psychosocial adversity, posttraumatic affective lability and aggression, posttraumatic psychiatric comorbidity, and overall disability than children who did not develop S-ADHD. CONCLUSIONS: There is an excess prevalence of premorbid ADHD among children who present with moderate and severe CHI. Children with high psychosocial adversity are more likely to develop S-ADHD after CHI. S-ADHD has criteria in common with personality change due to CHI, a deficit in behavioral inhibition being the major overlapping feature.

Adjusted variable plots for Cox's proportional hazards regression model.

Adjusted variable plots are useful in linear regression for outlier detection and for qualitative evaluation of the fit of a model. In this paper, we extend adjusted variable plots to Cox's proportional hazards model for possibly censored survival data. We propose three different plots: a risk level adjusted variable (RLAV) plot in which each observation in each risk set appears, a subject level adjusted variable (SLAV) plot in which each subject is represented by one point, and an event level adjusted variable (ELAV) plot in which the entire risk set at each failure event is represented by a single point. The latter two plots are derived from the RLAV by combining multiple points. In each point, the regression coefficient and standard error from a Cox proportional hazards regression is obtained by a simple linear regression through the origin fit to the coordinates of the pictured points. The plots are illustrated with a reanalysis of a dataset of 65 patients with multiple myeloma.

Some recent developments for regression analysis of multivariate failure time data.

Cox's seminal 1972 paper on regression methods for possibly censored failure time data popularized the use of time to an event as a primary response in prospective studies. But one key assumption of this and other regression methods is that observations are independent of one another. In many problems, failure times are clustered into small groups where outcomes within a group are correlated. Examples include failure times for two eyes from one person or for members of the same family. This paper presents a survey of models for multivariate failure time data. Two distinct classes of models are considered: frailty and marginal models. In a frailty model, the correlation is assumed to derive from latent variables ("frailties") common to observations from the same cluster. Regression models are formulated for the conditional failure time distribution given the frailties. Alternatively, marginal models describe the marginal failure time distribution of each response while separately modelling the association among responses from the same cluster. We focus on recent extensions of the proportional hazards model for multivariate failure time data. Model formulation, parameter interpretation and estimation procedures are considered.