scholarly journals Growth patterns of infants with in- utero HIV and ARV exposure in Cape Town, South Africa and Lusaka, Zambia

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Dorothy C. Nyemba ◽  
Emma Kalk ◽  
Michael J. Vinikoor ◽  
Hlengiwe P. Madlala ◽  
Mwangelwa Mubiana-Mbewe ◽  
...  
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Mixed Effects ◽  
Growth Patterns ◽  
Mixed Effects Models ◽  
World Health ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects ◽  
Increased Risk ◽  
In Pregnancy

Abstract Background Infants born HIV-exposed yet remain uninfected (HEU) are at increased risk of poorer growth and health compared to infants born HIV-unexposed (HU). Whether maternal antiretroviral treatment (ART) in pregnancy ameliorates this risk of poorer growth is not well understood. Furthermore, whether risks are similar across high burden HIV settings has not been extensively explored. Methods We harmonized data from two prospective observational studies conducted in Cape Town, South Africa, and Lusaka, Zambia, to compare weight-for-age (WAZ), length-for-age (LAZ) and weight-for-length (WLZ) Z-scores between infants who were HEU and HU, converting infant anthropometric measures using World Health Organisation Growth Standards adjusted for age and sex. Linear mixed effects models were fit to identify risk factors for differences in anthropometrics at 6–10 weeks and 6 months by infant HIV exposures status and by timing of exposure to maternal ART, either from conception or later in gestation. Results Overall 773 mother-infant pairs were included across two countries: women living with HIV (WLHIV), 51% (n = 395) with 65% on ART at conception and 35% initiating treatment in pregnancy. In linear mixed effects models, WAZ and WLZ at 6–10 weeks were lower among infants who were HEU vs HU [β = − 0.29 (95% CI: − 0.46, − 0.12) and [β = − 0.42 (95% CI: − 0.68, − 0.16)] respectively after adjusting for maternal characteristics and infant feeding with a random intercept for country. At 6 months, LAZ was lower [β = − 0.28 CI: − 0.50, − 0.06)] among infants who were HEU, adjusting for the same variables, with no differences in WAZ and WLZ. Within cohort evaluations identified different results with higher LAZ among infants who were HEU from Zambia at 6–10 weeks, [β = + 0.34 CI: + 0.01, + 0.68)] and lower LAZ among infants who were HEU from South Africa [β = − 0.30 CI: − 0.59, − 0.01)] at 6 months, without other anthropometric differences at either site. Conclusion Infant growth trajectories differed by country, highlighting the importance of studying contextual influences on outcomes of infants who were HEU.

scholarly journals Association of anticholinergic medications and AD biomarkers with incidence of MCI among cognitively normal older adults

Neurology ◽  
2020 ◽  
Vol 95 (16) ◽  
pp. e2295-e2304 ◽  
Author(s):  
Alexandra J. Weigand ◽  
Mark W. Bondi ◽  
Kelsey R. Thomas ◽  
Noll L. Campbell ◽  
Douglas R. Galasko ◽  
...  
Keyword(s):  
Risk Factors ◽  
Older Adults ◽  
Mixed Effects ◽  
Mixed Effects Models ◽  
Linear Mixed Effects Models ◽  
Cognitively Normal ◽  
Linear Mixed Effects ◽  
Anticholinergic Medications ◽  
Increased Risk ◽  
Risk Of Progression

ObjectiveTo determine the cognitive consequences of anticholinergic medications (aCH) in cognitively normal older adults as well as interactive effects of genetic and CSF Alzheimer disease (AD) risk factors.MethodsA total of 688 cognitively normal participants from the Alzheimer's Disease Neuroimaging Initiative were evaluated (mean age 73.5 years, 49.6% female). Cox regression examined risk of progression to mild cognitive impairment (MCI) over a 10-year period and linear mixed effects models examined 3-year rates of decline in memory, executive function, and language as a function of aCH. Interactions with APOE ε4 genotype and CSF biomarker evidence of AD pathology were also assessed.ResultsaCH+ participants had increased risk of progression to MCI (hazard ratio [HR] 1.47, p = 0.02), and there was a significant aCH × AD risk interaction such that aCH+/ε4+ individuals showed greater than 2-fold increased risk (HR 2.69, p < 0.001) for incident MCI relative to aCH−/ε4−), while aCH+/CSF+) individuals demonstrated greater than 4-fold (HR 4.89, p < 0.001) increased risk relative to aCH−/CSF−. Linear mixed effects models revealed that aCH predicted a steeper slope of decline in memory (t = −2.35, p = 0.02) and language (t = −2.35, p = 0.02), with effects exacerbated in individuals with AD risk factors.ConclusionsaCH increased risk of incident MCI and cognitive decline, and effects were significantly enhanced among individuals with genetic risk factors and CSF-based AD pathophysiologic markers. Findings underscore the adverse impact of aCH medications on cognition and the need for deprescribing trials, particularly among individuals with elevated risk for AD.

The Use of Theory of Linear Mixed-Effects Models to Detect Fraudulent Erasures at an Aggregate Level

2021 ◽  
pp. 001316442199489
Author(s):  
Luyao Peng ◽  
Sandip Sinharay
Keyword(s):  
Type I Error ◽  
Real Data ◽  
Mixed Effects ◽  
Error Rates ◽  
Mixed Effects Models ◽  
Type I ◽  
Aggregate Level ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects ◽  
Best Linear Unbiased

Wollack et al. (2015) suggested the erasure detection index (EDI) for detecting fraudulent erasures for individual examinees. Wollack and Eckerly (2017) and Sinharay (2018) extended the index of Wollack et al. (2015) to suggest three EDIs for detecting fraudulent erasures at the aggregate or group level. This article follows up on the research of Wollack and Eckerly (2017) and Sinharay (2018) and suggests a new aggregate-level EDI by incorporating the empirical best linear unbiased predictor from the literature of linear mixed-effects models (e.g., McCulloch et al., 2008). A simulation study shows that the new EDI has larger power than the indices of Wollack and Eckerly (2017) and Sinharay (2018). In addition, the new index has satisfactory Type I error rates. A real data example is also included.

scholarly journals Association of body condition with lameness in dairy cattle: a single-farm longitudinal study

2021 ◽  
pp. 1-4
Author(s):  
Michaela Kranepuhl ◽  
Detlef May ◽  
Edna Hillmann ◽  
Lorenz Gygax
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Mixed Effects ◽  
Mixed Effects Models ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects ◽  
Confounding Variables ◽  
Condition Score ◽  
The Impact ◽  
The Relationship

Abstract This research communication describes the relationship between the occurrence of lameness and body condition score (BCS) in a sample of 288 cows from a single farm that were repeatedly scored in the course of 9 months while controlling for confounding variables. The relationship between BCS and lameness was evaluated using generalised linear mixed-effects models. It was found that the proportion of lame cows was higher with decreasing but also with increasing BCS, increased with lactation number and decreased with time since the last claw trimming. This is likely to reflect the importance of sufficient body condition in the prevention of lameness but also raises the question of the impact of overcondition on lameness and the influence of claw trimming events on the assessment of lameness. A stronger focus on BCS might allow improved management of lameness that is still one of the major problems in housed cows.

D-optimal cohort designs for linear mixed-effects models

2007 ◽  
Vol 27 (14) ◽  
pp. 2586-2600 ◽  
Author(s):  
Fetene B. Tekle ◽  
Frans E. S. Tan ◽  
Martijn P. F. Berger
Keyword(s):  
Mixed Effects ◽  
Mixed Effects Models ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects
Sign in / Sign up

Export Citation Format

Share Document