A mixed method approach for using cross-sectional data for longitudinal inferences.
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Cross-Sectional Studies↗
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Results for “longitudinal data”
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[Evaluation of peripheral circulation in healthy children, according to data of longitudinal rheography].
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Adolescent↗
Comparative fitting of the Gompertz and logistic functions to longitudinal height data during adolescence in girls.
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Adolescent↗
[Longitudinal growth data of development of weight, height, skinfold thickness, head-, chest- and abdominal circumferences in healthy children (author's transl)].
From 1974--1977 anthropometric investigations were performed in 173 healthy infants during the first year of life. Weight, height, skinfold thickness, head-, chest-, and abdominal circumferences had been measured as parameters for growth. Birth weight increased ceased threefold on 12th month in males only. There is no difference in the increase of height in males and females. Width of skinfold thickness increases rapidly until month 5, except abdominal skinfold. A radual decrease follows thereafter. The difference in decreasing velocity of skinfold thickness indicates changes in distribution of subcutaneous fat tissue during infancy. Growth of head-, chest-, and abdominal circumferences of males are similar to that of females.
Abdomen↗
Longitudinal evidence of crystalline lens thinning in children.
PURPOSE: Most earlier studies indicated that the eye's crystalline lens grows continually throughout life, but cross-sectional results of crystalline lens thinning during childhood have been reported. The authors investigated crystalline lens thickness in childhood using cross-sectional and longitudinal data. METHODS: The Orinda Longitudinal Study of Myopia is a community-based study of normal eye growth and myopia development in school-age children. During a 1-to 3-year period, A-scan ultrasonographic lens thickness measurements of 869 children 6 through 14 years of age were analyzed. RESULTS: On average, between the ages of 6 and 10 years, the crystalline lens thins in its axial dimension by almost 0.2 mm. This thinning can be depicted by a cubic model. In this sample, the children with myopia had thinner crystalline lenses than the children with emmetropia of the same age. CONCLUSIONS: This article provides the first longitudinal evidence that the crystalline lens thins during the period of coordinated ocular growth between the ages of 6 and 10 years. Further, it shows that lens thickness is associated with refractive error. Thinner crystalline lenses in children with myopia may result from one of two underlying mechanisms: Either the crystalline lens exhausts its ability to compensate for axial elongation after undergoing accelerated lens thinning before the onset of myopia, or the crystalline lens in the myopic eye may be thinner throughout childhood, during which it thins at a rate consistent with other refractive errors. If mechanical forces link eye growth to crystalline lens compensation, more complex, visually guided feedback loops may not be needed to explain the normal eye growth that results in emmetropization.
Adolescent↗
Disability in activities of daily living: patterns of change and a hierarchy of disability.
OBJECTIVES: This paper examines longitudinal data over 6 years to evaluate incidence rates of disability and the pattern of dependency in activities of daily living. METHODS: The Longitudinal Study of Aging (n = 5151) was used to evaluate incidence of disability in activities of daily living; biennial interview data from 1984 through 1990 were used. The median age to disability onset for individual activities was estimated from survival analysis. A prevalent ordering of incident disability was identified from patterns of disability onset within individuals. RESULTS: The progression of incident disability among the elderly supported by longitudinal data, based on both the ordering of median ages to disability onset and patterns of incident disability, was as follows: walking, bathing, transferring, dressing, toileting, feeding. Gender differences were found in disability incidence rates. CONCLUSIONS: This study provides a mathematical picture of physical functioning as people age. These findings, based on longitudinal data, indicate a different hierarchical structure of disability than found in previous reports using cross-sectional data. Furthermore, the study documents gender differences in incident impairment, which indicate that although women outlive men, they spend more time in a disabled state.
Activities of Daily Living↗
Growth and development of West Indian children. Part I: Growth.
The growth of Caribbean infants is comparable to the NCHS standards until approximately 3 months of age despite somewhat lower birthweights. After this, growth rates decline. This pattern is similar to that seen in other developing countries (Condon-Paolini et al, 1977; Whitehead, 1979; Rowland et al, 1988). By 18 months of age, average weights and heights of Jamaican children approached the 10th centile of the NCHS standards and remained below the 40th centile throughout childhood. Ashcroft's studies of growth in childhood showed that the pattern of growth was similar in a number of countries in the Region but, in more recent nutritional surveys, differences between countries can be detected. For example, the prevalence of undernutrition is lower in Barbados but conversely obesity, especially in older girls, is becoming a significant problem. Most of the growth data on which this review is based was collected in the 1960s and early 1970s. Only a few studies provided longitudinal data. These were primarily those concerned with growth in the first year of life and the Lawrence Tavern study in which children were measured up to 4 years of age. There is clearly a need for more recent data, particularly longitudinal, since the available data suggest that secular changes are occurring. Surveys of nutritional status provide some information on the adequacy of growth but cannot be a substitute for measurements of normal growth patterns.
Child↗
Estimation and prediction with HIV-treatment interruption data.
We consider longitudinal clinical data for HIV patients undergoing treatment interruptions. We use a nonlinear dynamical mathematical model in attempts to fit individual patient data. A statistically-based censored data method is combined with inverse problem techniques to estimate dynamic parameters. The predictive capabilities of this approach are demonstrated by comparing simulations based on estimation of parameters using only half of the longitudinal observations to the full longitudinal data sets.
Antiretroviral Therapy, Highly Active↗
Prevalence and diagnosis of migraine in patients consulting their physician with a complaint of headache: data from the Landmark Study.
CONTEXT: Headache experts have suggested that to improve the recognition of migraine, patients with a stable pattern of episodic, disabling headache and a normal physical exam should be considered to have migraine in the absence of contradictory evidence. The premise upon which this approach is based-that is, that episodic, recurrent primary headache in the clinic is usually migraine-has not been evaluated in prospective clinical studies. OBJECTIVES: To (1) evaluate the diagnoses of patients consulting their physician with primary episodic headache and (2) compare clinic diagnoses and patient self-diagnoses with International Headache Society (IHS) headache diagnoses assigned on the basis of longitudinal data from patient diaries. DESIGN: Prospective, open-label study. During the screening visit, patients self-reported a headache diagnosis and then were assigned a headache diagnosis by their physician following his or her customary practice. Patients with a new physician diagnosis of migraine or nonmigraine primary headache were given diaries to record headache symptoms for up to 3 months or 6 attacks. Members of an expert panel, unaware of the clinic diagnosis, used diary data to assign a headache diagnosis to each attack and to each patient. SETTING: One hundred twenty-eight (128) practices in 15 countries including the United States. PATIENTS: A total of 1203 male and female patients between 18 and 65 years of age who consulted their physician with headache as a primary or secondary complaint. RESULTS: Overall, 94% of patients with a physician diagnosis of nonmigraine primary headache or a new clinic diagnosis of migraine had IHS-defined migraine (76%) or probable migraine (migrainous) (18%) headache on the basis of longitudinal diary data. A new clinic diagnosis of migraine was almost always correct: 98% of patients with a clinic diagnosis of migraine had IHS-defined migraine (87% of patients) or probable migraine (11% of patients) headache on the basis of longitudinal diary data. On the other hand, review of diaries of patients with a clinic diagnosis of nonmigraine revealed that 82% of these patients had IHS-defined migraine (48%) or probable migraine (34%) headache. Altogether, one in four patients (25%) with IHS-defined migraine according to longitudinal diary data did not receive a clinic diagnosis of migraine. CONCLUSIONS: These findings support the diagnostic approach of considering episodic, disabling primary headaches with an otherwise normal physical exam to be migraine in the absence of contradictory evidence. If in doubt of diagnosis or when assigning a nonmigraine diagnosis, strong consideration should be given to the use of a diary to confirm primary headache diagnosis.
Adolescent↗
Stochastic algorithms for Markov models estimation with intermittent missing data.
Multistate Markov models are frequently used to characterize disease processes, but their estimation from longitudinal data is often hampered by complex patterns of incompleteness. Two algorithms for estimating Markov chain models in the case of intermittent missing data in longitudinal studies, a stochastic EM algorithm and the Gibbs sampler, are described. The first can be viewed as a random perturbation of the EM algorithm and is appropriate when the M step is straightforward but the E step is computationally burdensome. It leads to a good approximation of the maximum likelihood estimates. The Gibbs sampler is used for a full Bayesian inference. The performances of the two algorithms are illustrated on two simulated data sets. A motivating example concerned with the modelling of the evolution of parasitemia by Plasmodium falciparum (malaria) in a cohort of 105 young children in Cameroon is described and briefly analyzed.
Algorithms↗
Applications of hierarchical linear models for evaluations of health interventions: demystifying the methods and interpretations of multilevel models.
Despite the wide availability of statistical programs designed to deal with longitudinal data from a multilevel perspective, many applied researchers remain unfamiliar with the benefits of this methodology, particularly for the evaluation of interventions. The authors present an example of multilevel modeling as part of the analysis of evaluation data from an HIV intervention study. Strategies for understanding multilevel models using longitudinal (panel) data are demonstrated and discussed. The authors illustrate how multiple linear regression models provide a convenient conceptual background to understanding how hierarchical linear models can be developed and interpreted. Multilevel analysis results are compared and contrasted with typical approaches through general linear models for repeated-measures data. Analyses are presented using the SPSS and HLM 5 software.
Analysis of Variance↗
Longitudinal study of child immunization determinants in China.
This paper exploits longitudinal data and methods to study the determinants of child immunization in 1990 s China. Many countries such as China are experiencing rapid economic transitions characterized by declining public health expenditures, privatizing health-care sectors, increased inequality and high income growth. It is still poorly understood how such changes affect utilization of preventive health care. Data from three waves of the China Health and Nutrition Survey were used to examine the immunization effects of child, household, and community health facility characteristics, as well as changes of such effects over time. Results indicate that gender and wealth differentials in immunization increased during China's transition, though these effects were small. The most important determinants were service price and maternal education. Wealth effects were minimal, indicating that the long-run effect of economic transition on immunization rates may depend crucially on the extent to which more rapid economic growth leads to increased educational investments. Methodologically, the paper finds substantial bias from standard cross-sectional models in contrast to panel data approaches, adding to the case for expanded collection of longitudinal health data in developing countries.
Child↗
Multilevel modeling for the analysis of longitudinal blood pressure data in the Framingham Heart Study pedigrees.
BACKGROUND: The data arising from a longitudinal familial study have a complex correlation structure that cannot be modeled using classical methods for the analysis of familial data at a single time point. METHODS: To fit the longitudinal systolic blood pressure (SBP) pedigree data arising from the Framingham Heart Study, we proposed to use multilevel modeling. That approach was used to distinguish multiple levels of information with individual repeated measurements (Level 1) being made within individuals (Level 2), and individuals clustered within pedigrees (Level 3). Residuals from the subject-specific and pedigree-specific regression models were summed both for the mean SBP and slope of SBP change over time, in order to define two new outcomes that were then used in a genome-wide linkage analysis. RESULTS: Evidence for linkage for the two outcomes (mean SBP and slope) was found in several chromosomal regions with a maximum LOD score of 3.6 on chromosome 8 and 3.5 on chromosome 17 for the mean SBP, and 2.5 on chromosome 1 for SBP slope. However, the linkage on chromosome 8 was only detected when the sample was restricted to subjects between age 25 and 75 and with at least four exams (Cohort 1) or 3 exams (Cohort 2). DISCUSSION: Multilevel modeling is a powerful approach to detect genes involved in complex traits when longitudinal data are available. It allows for complex hierarchical data structure to be taken into account and therefore, a better partitioning of random within-individual variation from other sources of variability (genetic or nongenetic).
Adult↗
Adjusting for covariates on a slippery slope: linkage analysis of change over time.
BACKGROUND: We analyzed the Genetic Analysis Workshop 13 (GAW13) simulated data to contrast and compare different methods for the genetic linkage analysis of hypertension and change in blood pressure over time. We also examined methods for incorporating covariates into the linkage analysis. We used methods for quantitative trait loci (QTL) linkage analysis with and without covariates and affected sib-pair (ASP) analysis of hypertension followed by ordered subset analysis (OSA), using variables associated with change in blood pressure over time. RESULTS: Four of the five baseline genes and one of the three slope genes were not detected by any method using conventional criteria. OSA detected baseline gene b35 on chromosome 13 when using the slope in blood pressure to adjust for change over time. Slope gene s10 was detected by the ASP analysis and slope gene s11 was detected by QTL linkage analysis as well as by OSA analysis. Analysis of null chromosomes, i.e., chromosomes without genes, did not reveal significant increases in type I error. However, there were a number of genes indirectly related to blood pressure detected by a variety of methods. CONCLUSIONS: We noted that there is no obvious first choice of analysis software for analyzing a complicated model, such as the one underlying the GAW13 simulated data. Inclusion of covariates and longitudinal data can improve localization of genes for complex traits but it is not always clear how best to do this. It remains a worthwhile task to apply several different approaches since one method is not always the best.
Blood Pressure↗
Long-range antecedents of functional capability in later life.
A number of demographic, social, psychological, lifestyle, and health characteristics have been advanced as precursors of functional limitation among those who survive to old age. This study uses data from a 16-year longitudinal study to examine long-range antecedents of the respondents' level of physical functional capability in 1991. The model predicting functional capability from longitudinal data is more complex and more effective for women than for men. Older age, lower self-rated health, lower functional capability, and lower physical activity level in 1975 predict 35% of the variation in functional capability among women in 1991. Only older age and lower self-rated health are predictive for men and account for just 11% of the variation. These findings suggest a need for gender-specific models of antecedents of physical functional limitations in later life.
Activities of Daily Living↗
Differences in onset and persistence of substance abuse and dependence among whites, blacks, and Hispanics.
OBJECTIVE: This article describes patterns of onset, persistence, and cessation of substance abuse among whites, blacks, and Hispanics that are masked in cross-sectional prevalence data. METHODS: The authors analyzed longitudinal data from a sample of 1,004 white, black, and Hispanic respondents from Chicago to investigate processes of onset, persistence, and cessation of substance abuse and dependence for two age cohorts, 15 and 18 at baseline and 17 and 20 at follow-up. RESULTS: The data show few racial or ethnic differences in the prevalence of alcohol and marijuana abuse and dependence at age 15. Rates of onset of alcohol abuse and dependence among whites between ages 15 and 17 were significantly higher than for blacks and Hispanics, and the rates of onset of marijuana abuse and dependence among blacks between ages 18 and 20 were significantly higher than for whites and Hispanics of the same age group. There were few significant differences among the three groups in the persistence rates of abuse and dependence. CONCLUSION: By age 20 the rates of marijuana abuse and dependence are significantly higher among blacks than among whites and Hispanics.
Adolescent↗
Development of individual growth curve standards for estimated fetal weight: I. Weight estimation procedure.
In this investigation the weight estimation procedure of Rossavik was reassessed with particular emphasis on parameter estimation and performance over a wide weight range. Using a cross-sectional data set (193 patients), a longitudinal data set (20 patients), and an iterative procedure, parameter estimates were obtained based solely on regression analysis. Comparison of weight estimates obtained using a function based on these parameter values with actual birth weights indicated virtually no systematic errors over a 250-g to 4750-g weight range and random errors (+/- 1 SD) of 10% to 13% below 200 g and 6% to 8% above 2000 g. The weights of small- and large-for-gestational age fetuses were systematically overestimated (4.1%) and underestimated (-3.0%), respectively, but systematic errors were not found in average-for-gestational age fetuses. No differences in random errors were seen in these three growth categories. Comparison with other weight estimation procedures indicated that the Rossavik procedure gives weight estimates that are at least as accurate as those obtained with other methods over a wide range of weight and growth categories. However, the Rossavik procedure can be used to generate individual growth curve standards for weight estimates, a characteristic not shared with other weight estimation procedures.
Birth Weight↗
Inhalants to heroin: a prospective analysis from adolescence to adulthood.
Recent cross-sectional studies have indicated that inhalant use might be a vulnerability marker for the development of heroin use. This study is the first prospective investigation of the hypothesized association between early inhalant use and later heroin use. Analyses were conducted using longitudinal data from a community sample of Woodlawn (an all African American community on the South side of Chicago). Six-hundred subjects participated in both the adolescent and the adult assessments (approximately ages 16 and 32, respectively). Youths with a history of inhalant use by age 16 were over nine times more likely to begin heroin use by age 32, even when other plausible risk factors for the development of heroin use were held constant (RR = 9.3; 95% C.I. = 1.3 - 51.3). These findings add to and are consistent with prior cross-sectional evidence from data based on treatment samples and national survey data. The results from this longitudinal assessment support the idea that youthful inhalant use should be regarded as a vulnerability marker for the development of more serious drug use involvement in the form of heroin use.
Administration, Inhalation↗