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Multilevel Regression Analyses (multilevel + regression_analysis)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Subtle gene,environment interactions driving paranoia in daily life

GENES, BRAIN AND BEHAVIOR, Issue 1 2009
C. J. P. Simons
It has been suggested that genes impact on the degree to which minor daily stressors cause variation in the intensity of subtle paranoid experiences. The objective of the present study was to test the hypothesis that catechol- O -methyltransferase (COMT) Val158Met and brain-derived neurotrophic factor (BDNF) Val66Met in part mediate genetic effects on paranoid reactivity to minor stressors. In a general population sample of 579 young adult female twins, on the one hand, appraisals of (1) event-related stress and (2) social stress and, on the other hand, feelings of paranoia in the flow of daily life were assessed using momentary assessment technology for five consecutive days. Multilevel regression analyses were used to examine moderation of daily life stress-induced paranoia by COMT Val158Met and BDNF Val66Met genotypes. Catechol- O -methyltransferase Val carriers displayed more feelings of paranoia in response to event stress compared with Met carriers. Brain-derived neurotrophic factor Met carriers showed more social-stress-induced paranoia than individuals with the Val/Val genotype. Thus, paranoia in the flow of daily life may be the result of gene,environment interactions that can be traced to different types of stress being moderated by different types of genetic variation. [source]

Biological, social, and community influences on third-grade reading levels of minority Head Start children: A multilevel approach

JOURNAL OF COMMUNITY PSYCHOLOGY, Issue 3 2003
Virginia A. Rauh
The purpose of the study was to determine the impact of individual and community level risks on school outcomes of children who attend Head Start. We studied a sample of 3,693 African American and Hispanic children who had been born in New York City, participated in Head Start, and attended New York City public schools. The outcome was the score obtained on a citywide third-grade reading test. Individual level risk factors were derived from birth certificate data. Community level risks were extracted from citywide U.S. Census data and other public-access data sets. Multilevel regression analyses indicated that at the individual level, lower reading scores were significantly associated with: male gender, low birth weight, unmarried mother, low maternal education, and inadequate interpregnancy spacing. Controlling for individual-level risk, concentrated community poverty significantly lowered reading scores, and a high percentage of immigrants in the community significantly raised scores. There was also a significant crosslevel effect: boys benefited more than girls from the immigrant community effect. The evidence suggests that we can better identify children at future educational risk and maximize the success of early intervention programs by exploring influences on school success at multiple levels, including the community. © 2003 Wiley Periodicals, Inc. J Comm Psychol 31: 255,278, 2003. [source]

Is Marriage More Than Cohabitation?

JOURNAL OF MARRIAGE AND FAMILY, Issue 5 2009
Well-Being Differences in 30 European Countries
The study aims to assess, first, whether there is a gap in well-being between unmarried cohabitants and the married, second, if selection factors can explain this so-called cohabitation gap, and third, if the size of the cohabitation gap differs across countries and how this can be explained. We use pooled data from young adults (18,44) in 3 rounds of the European Social Survey (N , 31, 500). Multilevel regression analyses show that there is a moderate cohabitation gap that can be partly explained with the selection factors material resources and religiosity. Country differences were clear and could partly be explained with the level of institutionalization: In countries where cohabitation is more accepted and more prevalent, the cohabitation gap is smaller. [source]

Effect of aging and degeneration on disc volume and shape: A quantitative study in asymptomatic volunteers

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2006
Christian W. A. Pfirrmann
Abstract Debate continues on the effect of disc degeneration and aging on disc volume and shape. So far, no quantitative in vivo MRI data is available on the factors influencing disc volume and shape. The objective of this MRI study was to quantitatively investigate changes in disc height, volume, and shape as a result of aging and/or degeneration omitting pathologic (i.e., painful) disc alterations. Seventy asymptomatic volunteers (20,78 years) were investigated with sagittal T1- and T2-weighted MR-images encompassing the whole lumbar spine. Disc height was determined by the Dabbs method and the Farfan index. Disc volume was calculated by the Cavalieri method. For the disc shape the "disc convexity index" was calculated by the ratio of central disc height and mean anterior/posterior disc height. Disc height, disc volume, and the disc convexity index measurements were corrected for disc level and the individuals age, weight, height, and sex in a multilevel regression analysis. Multilevel regression analysis showed that disc volume was negatively influenced by disc degeneration (p,<,0.001) and positively correlated with body height (p,<,0.001) and age (p,<,0.01). Mean disc height and the disc convexity index were negatively influenced by disc degeneration but not by gender, weight, and height. Disc height was positively correlated with age (p,<,0.01). From the results of this study, it can be concluded that disc degeneration generally results in a decrease of disc height and volume as well as a less convex disc shape. In the absence of disc degeneration, however, age tends to result in an inverse relationship on disc height, volume, and shape. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source]

The infrabony defect and its determinants

JOURNAL OF PERIODONTAL RESEARCH, Issue 6 2006
C. -K.
Background and Objective:, The purpose of this study was to assess the defect width of infrabony defects in a cross-sectional study and to evaluate whether the defect width is a function of defect depth. Material and Methods:, Complete sets of intra-oral radiographs of patients with severe periodontitis, which exhibited at least one infrabony defect, were digitised and evaluated. The following parameters were measured: depth and width of the infrabony defect, defect angle, and width of the interdental spaces. Results:, Fifty-one patients (26 women), ranging from 21 to 73 yr of age (48.5 ± 13.4 yr), contributed a total of 1272 teeth with 135 infrabony defects (10.6%). Seventeen infrabony defects were located at sites without a neighboring tooth. Infrabony defects were statistically more prevalent in the mandible (n = 82) than in the maxilla (p = 0.013), and more prevalent at mesial sites (n = 92) than at distal sites (p < 0.001). At infrabony defects, the width of interdental spaces at the most coronal extension of the alveolar crest could be measured only at sites with neigboring teeth 2.67 ± 0.78 mm (range: 1.19,5.70 mm). Analysis failed to reveal a statistically significant difference between defect width at sites with (2.64 ± 0.82 mm) and sites without (2.76 ± 0.70 mm) a neighboring tooth. Multilevel regression analysis revealed narrow defect angles to be related to deep infrabony defects, whereas width of the interdental space and distal location were related to wide defects. Conclusion:, Defect angle depended on defect depth and defect width was not different at sites with or without a neighboring tooth. Even in severe periodontitis, infrabony defects are found only at a minority of teeth. [source]