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Results for “longitudinal data”

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PubMed2000

The evolution of volunteerism and professional staff within hospice care in North Carolina.

Although the pursuit of Medicare certification has been one of the most controversial events in hospice history no study has examined its impact using data from a defined population of hospices before, during, and after federal legislation was enacted. This paper revisits the debate over the changing role of volunteers using such a longitudinal data source. Over time, as the patient population grew, aggregate levels of volunteers and professional staff increased. However, the ratios of professional staff and volunteers to patients reveal that regardless of certification status, hospices retained more professional staff per patient and fewer volunteers per patient over time. These data suggest hospices, particularly certified organizations, have transitioned from voluntary organizations to professionally staffed organizations with a strong volunteer component. The most important issue for future research is whether the observed changes have affected the quality of hospice care.

Accreditation↗

PubMed1999

Impact of a school-based interdisciplinary intervention on diet and physical activity among urban primary school children: eat well and keep moving.

OBJECTIVE: To evaluate the impact of a school-based interdisciplinary health behavior intervention on diet and physical activity among children in grades 4 and 5. DESIGN: A quasiexperimental field trial with 6 intervention and 8 matched control schools. Outcomes were assessed longitudinally using preintervention (fall 1995) and follow-up (spring 1997) student survey food frequency and activity measures and follow-up 24-hour recall measures of diet and activity. Change was also assessed using yearly repeated cross-sectional surveys of all grade 5 students from 1995 through 1997. PARTICIPANTS: Longitudinal data were collected from 479 students initially in grade 4 in Baltimore, Md, public schools; 91% were African American. Repeated 24-hour recall measures in 1997 were collected for a random subsample of 336 students. Cross-sectional survey data were collected from all grade 5 students in 1995,1996, and 1997 (n = 2103). INTERVENTION: The Eat Well and Keep Moving Program was taught by classroom teachers over 2 years in math, science, language arts, and social studies classes. Materials provided links to school food services and families and provided training and wellness programs for teachers and other staff members. Intervention materials focused on decreasing consumption of foods high in total and saturated fat and increasing fruit and vegetable intake, as well as reducing television viewing and increasing physical activity. MAIN OUTCOME MEASURES: Dietary intake and physical activity measured via repeated 24-hour recall were primary end points, with additional food frequency and activity measures. RESULTS: The 24-hour recall measures indicated that, after controlling for baseline covariates, the percentages of total energy from fat and saturated fat were reduced among students in intervention compared with control schools (-1.4%; 95% confidence interval [CI], -2.8 to -0.04; P = .04 and -0.60%; 95% CI, -1.2 to -0.01; P = .05). There was an increase in fruit and vegetable intake (0.36 servings/4184 kJ; 95% CI, 0.10-0.62; P=.01), in vitamin C intake (8.8 mg/4184 kJ; 95% CI, 2.0-16; P=.01), and in fiber consumption (0.7 g/4184 kJ; 95% CI, 0.0-1.4; P=.05). Television viewing was marginally reduced (-0.55 h/d; 95% CI, -1.04 to 0.04; P=.06). Analysis of longitudinal and repeated cross-sectional food frequency data indicated similar significant decreases in the percentages of total energy from fat and saturated fat. CONCLUSION: Evaluation of the Eat Well and Keep Moving Program indicates effectiveness in improving dietary intake of students and reducing television viewing.

Baltimore↗

PubMedDate not supplied

An examination of the definition 'final height' for practical use.

Determining which of various 'final height' definitions is most applicable to the data sets is a useful preceding step for studies concerning adult stature prediction. This paper presents an examination of three definitions and their validity when practically applied to two different longitudinal data sets. Two data series examined in this study are T-data (31 boys and 35 girls born between 1967 and 1978) and H-data (113 girls born between 1956 and 1966). Three definitions of final height applied to the data are: (1) Final stature at 18 years of age (Fht (18)); (2) Stature after a year with an annual increment less than 0.5 cm (Fht (0.5)); and (3) The highest measurement (Fht (hst)). The results of this study suggest the greatest height of an individual measurement (Fht (hst)) is the most effective definition of 'final stature' for practical use. This definition can be applied to various types of data, whether measurements are obtained from individuals during school periods, or whether measurements are obtained from individuals until the cessation of growth.

Adolescent↗

PubMed2003

Corpus callosum development in childhood-onset schizophrenia.

OBJECTIVE: Corpus callosum (CC) size and interhemispheric communication differences have been reported between patients with schizophrenia and normal controls. Childhood-onset schizophrenia (COS) is a severe form of the disorder that is continuous with later-onset disorder. Corpus callosal area was examined for COS at initial scan and prospectively through adolescence, and related to other developmental abnormalities for this group. METHOD: A total of 113 anatomic brain MRI scans were obtained from 55 COS (22 female) and 110 scans from 56 age- and gender-matched healthy volunteers (22 female), across ages 8-24. Baseline and prospective rescans were obtained at approximately 2-year intervals. The midsagittal areas for total corpus callosum and seven subregions were calculated using an automated system. Cross-sectional and longitudinal data were combined using mixed model regression analysis to compare developmental changes for the two groups. RESULTS: No diagnostic differences were seen at time of initial scan. Longitudinally, and in contrast to healthy volunteers, patients with schizophrenia showed a significant difference in developmental trajectory for the area of the splenium, both before (p=0.012) and after (p=0.05) adjustment for total cerebral volume. The area of the splenium becomes significantly smaller in COS, starting at about age 22. CONCLUSION: Patients with schizophrenia showed a significant difference in developmental trajectory for the splenial area, which seems to decline for COS. If replicated, this may reflect anticipated late occipital and extrastriate changes in brain regions.

Adolescent↗

PubMed2004

Sensitivity analysis for pattern mixture models.

Incomplete series of data is a common feature in quality-of-life studies, in particular in chronic diseases where attrition of patients is high. Two alternative approaches to modeling longitudinal data with incomplete measurements have frequently been proposed in the literature, selection models and pattern-mixture models. In this paper we focus on, by way of sensitivity analysis, extrapolating incomplete patterns using identifying restrictions. Perhaps the best known ones are so-called complete case missing value restrictions (CCMV), where for a given pattern, the conditional distribution of the missing data, given the observed data, is equated to its counterpart in the completers. Available case missing value (ACMV) restrictions equate this conditional density to the one calculated from the subgroup of all patterns for which all required components have been observed. Neighboring case missing value restrictions (NCMV) equate this conditional density to the one calculated from the the pattern with one additional measurement obtained. In this paper, these three identifying restriction strategies are used to multiply impute missing data in a study in metastatic prostate cancer. Multiple imputation is employed to reduce the uncertainty of single imputation. It is shown how hypothesis testing and sensitivity analyses are carried out in this setting.

Humans↗

PubMed1995

Thermic effect of food in humans: methods and results from use of a respiratory chamber.

During the past two decades, many investigators have measured the thermic effect of food (TEF) in humans and have speculated on its role in the development of obesity. In this study we compared different ways of computing TEF from daily energy expenditure measurements in a respiratory chamber, evaluated the determinants of TEF, and more importantly assessed for the first time the relation between TEF and change in body weight. In 471 subjects, TEF was 1697 +/- 857 kJ/d (mean +/- SD), ie, 18 +/- 9% of energy intake. In 114 subjects studied more than once, intraindividual TEF variability was very high (CV = 48%). TEF correlated positively with the level of spontaneous physical activity (SPA) and negatively with fasting plasma glucose and insulin concentrations. TEF correlated inversely with age (males only) and body weight, percent body fat, and waist-to-hip ratio (females only). The level of SPA and fasting plasma glucose concentration were the only significant determinants of TEF, explaining 15% of its variance. In 137 subjects in whom body weight was measured > or = 6 mo after TEF measurement (mean follow-up duration of 2.9 +/- 1.7 y), a low TEF was not predictive of body weight gain. We conclude that, despite the low reproducibility of TEF from use of a respiratory chamber, data in a large number of subjects suggest that TEF is increased by higher SPAs and that insulin resistance is associated with a low TEF. More important, longitudinal data indicate that the variability in TEF is not associated with changes in body weight.

Adolescent↗

PubMed1981

A dynamic analysis of chronic disease development: a study of sex specific changes in coronary heart disease incidence and risk factors in Framingham.

An analysis of sex differentials in the dynamics of coronary heart disease (CHD) in the Framingham study is conducted using a methodology designed process which aids in the interpretation of the longitudinal results. This methodology permits the analysis of risk variable changes over time to be conducted independently of the analysis of the relation of risk variable values to CHD risk. The independent analyses afford a complete utilisation of information from longitudinal studies of chronic disease risk and produce insights into the dynamics of chronic disease development not available by other analytic strategies. The results of this analysis are compared with results obtained from a similarly structured multiple logistic analysis--a comparison which illustrates some of the technical and conceptual deficiencies of the often employed multiple logistic analysis when applied to longitudinal data.

Adult↗

PubMed2000

Socioeconomic status and dissatisfaction among HMO enrollees.

OBJECTIVES: Member satisfaction is commonly used as an indicator of the quality of care delivered by health plans. Yet few contemporary studies have explored the extent to which individual patient characteristics influence dissatisfaction in HMOs. We sought to determine whether socioeconomic status is associated with enrollee dissatisfaction. METHODS: Data are from a cross-sectional, telephone survey of a probability sample of adults enrolled in New Jersey HMOs in 1998 (n = 7,983). Health plan ratings were elicited as part of the Consumer Assessment of Health Plans Study (CAHPS) survey, along with income, education, and race/ethnicity. Other factors known to influence satisfaction (age, gender, health status, extent of plan choice, and payment for plan) were also ascertained. RESULTS: Socioeconomically advantaged enrollees were more likely to give low ratings to their health plans. In a multivariate logistic regression model, those with incomes exceeding $100,000 had 1.65 times the odds of being dissatisfied compared with those with family incomes less than $25,000 (P <0.001); those with a college education had 2.53 times the odds of being dissatisfied than those who had not completed high school (P <0.001). However, among enrollees in their plans for > or =5 years, those in the lowest income group were significantly more dissatisfied than higher-income enrollees. CONCLUSIONS: Among New Jersey HMO enrollees, higher socioeconomic status (SES) is associated with greater dissatisfaction. Although based on cross-sectional data and thus preliminary, the evidence presented here also suggests that the SES-dissatisfaction relationship varies as a function of duration of enrollment. Further research using longitudinal data could shed additional light on the SES-dissatisfaction link.

Adolescent↗

PubMed2002

National Committee on Quality Assurance health-plan accreditation: predictors, correlates of performance, and market impact.

CONTEXT: Accreditation of health care organizations has traditionally been considered a building block of quality assurance. However, the differences between accredited and nonaccredited health plans and the impact of accreditation on plan enrollment are not well understood. OBJECTIVES: To determine the characteristics of plans that have submitted to accreditation review, the performance of accredited plans on quality indicators and the impact of accreditation on enrollment. DESIGN: The databases containing 1996 data on health plans' National Committee on Quality Assurance (NCQA) accreditation status, organizational characteristics, Health Plan Employer Data and Information Set (HEDIS) scores, and patient-reported quality and satisfaction scores were linked to compare accredited health plans to nonaccredited plans. We also combined longitudinal data sets (1993-1998) on accreditation and health plan enrollment. MAIN OUTCOME MEASURES: Mean performance of accredited and nonaccredited plans on HEDIS measures and patient-reported measures of quality; health plan enrollment changes. RESULTS: Accredited plans have higher HEDIS scores but similar or lower performance on patient-reported measures of health plan quality and satisfaction. Furthermore, a substantial number of the plans in the bottom decile of quality performance were accredited suggesting that accreditation does not ensure high quality care. Receipt of accreditation has been associated with increased enrollment in the early years of the accreditation program; however, plans denied NCQA accreditation do not appear to suffer enrollment losses. CONCLUSION: NCQA accreditation is positively associated with some measures of quality but does not assure a minimal level of performance. Efforts now underway to incorporate plan performance on HEDIS into criteria for accreditation seem warranted.

Accreditation↗

PubMed1992

SSI case closures.

In 1990, about 800,000 persons receiving payments from the Supplemental Security Income (SSI) program had their cases closed and their payments stopped. The most frequently cited reasons for these case closures were excess income and death. Of those cases closed for reasons other than death, about 43 percent eventually returned to payment status. This study presents an analysis of a 1-percent sample of SSI recipients whose cases were closed during 1990. Longitudinal data on closures were collected by merging a series of monthly 1-percent sample files containing SSI administrative data. These are the first published data on reasons for SSI case closures.

Adolescent↗

PubMed2002

Poor uterine development in Turner syndrome with oral oestrogen therapy.

OBJECTIVE: To evaluate uterine development in Turner syndrome (TS) patients in relation to treatment with oral ethinyl oestradiol (E2 ) for pubertal induction. DESIGN AND PATIENTS: Pelvic ultrasound data for 96 TS patients scanned since 1989 were analysed. Patients were classified into three groups: (1) untreated (n = 48); (2) complete spontaneous puberty (n = 10); and (3) treated with ethinyl oestradiol (n = 38). Uterine development was described in the three groups and compared with the normal data. MEASUREMENTS: Uterine length, fundal-cervical ratio (FCR) and shape were recorded, and presence or absence of ovaries noted. In the treated group, cross-sectional and longitudinal data were combined to compare uterine development with Tanner breast stage. RESULTS: In untreated girls up to age 10 years there was a variable distribution of uterine length and FCR about the mean. Thereafter, the uterus failed to grow and mature normally. Girls with complete spontaneous puberty had morphologically normal ovaries and uteri, but of 7 girls who attained menarche, 3 subsequently developed secondary oligomenorrhoea or amenorrhoea. In the treated group, in general, breast development and uterine length progressed with increasing E2 dose. However, only 50% of girls with complete secondary sexual development had a mature heart-shaped uterine configuration. CONCLUSIONS: Our current E2 treatment regimen for TS girls gives rise to satisfactory pubertal induction and maintenance, but failed to induce a fully mature uterus in half the cohort. In view of the high risk of miscarriage in TS in both spontaneous and assisted pregnancies, the effect of more physiological methods of E2 replacement on uterine development should be investigated.

Adolescent↗

PubMedDate not supplied

Staging the menopausal transition: data from the TREMIN Research Program on Women's Health.

The present study was conducted to test the assumptions of a staging system of reproductive aging that was proposed at the Stages of Reproductive Aging Workshop (STRAW) in 2001. Using longitudinal data provided by 100 women over a period of 3-12 years, we asked whether midlife women move in a uniform progression from pre- to peri- to postmenopause, as refuted by earlier studies but proposed by the STRAW model, or whether they differ from this assumed pattern. Participants were recruited from the TREMIN Research Program on Women's Health, the oldest ongoing study of menstruation and women's health in the world. Eligibility criteria included reaching menopause during the course of the study and not using exogenous hormones. Participants provided annual self-reports of menopausal stage based on observations of their menstrual cycles ("regular," "changing," and "menopausal"). Findings revealed a lack of uniformity as women progressed toward menopause. From 8 to over 20 different perimenopausal stage patterns were observed, depending on the analysis. While the most common pattern was to progress from regular to changing to menopause, some women experienced menstrual bleeding after a year or more of amenorrhea, others flip-flopped between stages, and still others skipped directly from regular bleeding to menopause. We conclude that there is considerable variation in women's movement across menopausal status categories and urge researchers to accommodate such findings in their model building.

Adult↗

PubMed1993

Bone mass among premenopausal women.

Bone mass in early adult life, or peak bone mass, is primarily under genetic control, although recent data suggest that alterations in nutrition and life style during growth may modify the genetic potential. Cross-sectional data indicated that upon completion of growth, there was a period of skeletal consolidation that resulted primarily from increased width of cortical bones. Data on cancellous bone are conflicting. Cross-sectional data suggest that cancellous bone mass reaches a maximum at about age 18 years. Bone mass in the spine appears stable until the beginning of menopause, unless there are other disturbances of ovarian function. On the basis of cross-sectional data, significant bone loss in the femoral neck in premenopausal women appears to occur prior to changes in ovarian function. This decline in hip density is also independent of body size, nutritional influences, or other variables thought to influence bone mass. Longitudinal data are not available to confirm the reduction in femoral neck bone mass. Preliminary data indicate that modest disruptions of ovarian function, insufficient to result in frank amenorrhea, might impact negatively on bone mass. A detailed longitudinal study of menstrual and other factors controlling bone mass in premenopausal women is needed. If bone mass can be modified, ensuring a maximal skeletal mass becomes a viable possibility for prevention of osteoporosis.

Adolescent↗

PubMed2006

Parenting behaviors associated with risk for offspring personality disorder during adulthood.

CONTEXT: Research has suggested that some types of parental child-rearing behavior may be associated with risk for offspring personality disorder (PD), but the association of parenting with offspring PD has not been investigated comprehensively with prospective longitudinal data. OBJECTIVE: To investigate the association of parental child-rearing behavior with risk for offspring PD during adulthood. DESIGN: The Children in the Community study, a prospective longitudinal investigation. SETTING AND PARTICIPANTS: A community-based sample of 593 families interviewed during childhood (mean age, 6 years), adolescence (mean ages, 14 and 16 years), emerging adulthood (mean age, 22 years), and adulthood (mean age, 33 years) of the offspring. MAIN OUTCOME MEASURE: The Structured Clinical Interview for DSM-IV Personality Disorders. RESULTS: Ten types of parenting behavior that were evident during the child-rearing years were associated with elevated offspring risk for PD during adulthood when childhood behavioral or emotional problems and parental psychiatric disorders were controlled statistically. Parental behavior in the home during the child-rearing years was associated with elevated risk for offspring PD at mean ages of 22 and 33 years. Risk for offspring PD at both assessments increased steadily as a function of the number of problematic parenting behaviors that were evident. Low parental affection or nurturing was associated with elevated risk for offspring antisocial (P = .003), avoidant (P = .01), borderline (P = .002), depressive (P = .02), paranoid (P = .002), schizoid (P = .046), and schizotypal (P<.001) PDs. Aversive parental behavior (eg, harsh punishment) was associated with elevated risk for offspring borderline (P = .001), paranoid (P = .004), passive-aggressive (P = .046), and schizotypal (P = .02) PDs. CONCLUSIONS: Parental behavior during the child-rearing years may be associated with risk for offspring PD that endures into adulthood. This risk may not be attributable to offspring behavioral and emotional problems or parental psychiatric disorder, and it may not diminish over time. Low parental nurturing and aversive parental behavior during child rearing may both be associated with elevated risk for offspring PDs.

Adolescent↗

PubMed2004

Functional magnetic resonance imaging (magnetization transfer) and stereological analysis of human placentae in normal pregnancy and in pre-eclampsia and intrauterine growth restriction.

Magnetic resonance imaging provides a non-invasive method for investigating functional changes in the human placenta in vivo. In this study, we combine a magnetic resonance imaging technique called magnetization transfer with established stereological methods in order to analyse and compare placentae from normal (16-36 weeks of gestation) and complicated (pre-eclampsia, intrauterine growth restriction) pregnancies. Magnetization transfer provided an in vivo measure of the ratio of bound protons:total protons and stereological analysis of histological sections was used to estimate a residual:total volume ratio (the ratio of non-vascular volume to total placental volume). Statistical comparisons were drawn using tests for related samples (longitudinal data) or one-way analysis of variance (cross-sectional data). We found no significant differences in magnetization transfer between gestational age groups or between uncomplicated pregnancies and pregnancies complicated by pre-eclampsia or intrauterine growth restriction. In comparable groups of different subjects, stereological analyses also failed to demonstrate significant differences in residual:total volume ratios. We conclude that [a] the ratio of non-vascular volume:total placental volume does not alter between 16 and 36 weeks of normal gestation, and [b] this integrated response is also conserved in pre-eclampsia and intrauterine growth restriction.

Birth Weight↗

PubMed2004

An active and socially integrated lifestyle in late life might protect against dementia.

The recent availability of longitudinal data on the possible association of different lifestyles with dementia and Alzheimer's disease (AD) allow some preliminary conclusions on this topic. This review systematically analyses the published longitudinal studies exploring the effect of social network, physical leisure, and non-physical activity on cognition and dementia and then summarises the current evidence taking into account the limitations of the studies and the biological plausibility. For all three lifestyle components (social, mental, and physical), a beneficial effect on cognition and a protective effect against dementia are suggested. The three components seem to have common pathways, rather than specific mechanisms, which might converge within three major aetiological hypotheses for dementia and AD: the cognitive reserve hypothesis, the vascular hypothesis, and the stress hypothesis. Taking into account the accumulated evidence and the biological plausibility of these hypotheses, we conclude that an active and socially integrated lifestyle in late life protects against dementia and AD. Further research is necessary to better define the mechanisms of these associations and better delineate preventive and therapeutic strategies.

Aged↗

PubMed1993

Longitudinal statistical models for loss of sound surfaces.

Longitudinal data of 50-yr-old men, followed for 10 yr, were analyzed to identify variables which may be associated with healthy tooth surface loss. Three types of longitudinal models were used, arriving at similar conclusions. Predictors of sound tooth surface loss with aging included pocket depth, mobility, and recession.

Aging↗

PubMed1994

Epidemiologic study of sound surface trends in a 10-year longitudinal study.

Longitudinal data of 589 men aged 30-65 yr, each followed for 10 yr, were analyzed to identify variables which may be associated with healthy tooth surface loss. A longitudinal linear growth curve model was used. As expected, older cohorts tended to have fewer sound surfaces (P < 0.02), but they also tended to have greater rates of sound surface loss (P < 0.01). Age, bone loss, number of teeth at baseline, gingivitis, pocket depth and calculus were individually correlated (P < 0.05) with the rate of sound surface loss. The number of filled or diseased surfaces at baseline was also marginally correlated (P < 0.06) with rate of sound surface loss.

Adult↗