1
|
Low D, Leroux A, Urbanek J, Crainiceanu C. 1043 The Relationship Between Nighttime Eating And Body Mass Index. Sleep 2020. [DOI: 10.1093/sleep/zsaa056.1039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Introduction
Late night eating has been associated with higher odds of being overweight or obese. This study aims to evaluate the relationship between late night eating and body mass index in a nationally representative sample.
Methods
Actigraphy was used to estimate the average bedtime, waketime, duration and midpoint of sleep in the National Health and Nutrition Examination Survey 2003-04 and 2005-06 cohorts. Given the circular nature of clock time, the average was calculated to be the point that minimized the sum of squares of differences between time points. Dietary data was collected through two detailed interviews of the participants. Nighttime calories were defined as the average amount of calories consumed between the average bedtime and the average midpoint of time-in-bed, based on the data recorded during the dietary interviews.
Results
Higher average nighttime caloric consumption (in units of 100 kcal) was associated with higher BMI [B(95% CI): 0.062 (0.003, 0.121)]; this remained significant after adjustment for age, gender, and race [B(95% CI): 0.084 (0.026, 0.142)]. Higher nighttime caloric consumption (as a percentage of total average daily calories consumption) was associated with higher BMI [B(95% CI): 1.522 (0.312, 2.733)]. This remained significant after adjustment for age, gender, and race [B(95% CI): 1.718 (0.505, 2.931)].
Conclusion
Higher nighttime caloric consumption, both in average amount (in units of 100 kcal) and as a percentage of average daily calories consumption, was associated with higher BMI. Additional study is needed to further elucidate the relationship between nighttime eating habits and body mass index.
Support
NHLBI T32HL110952
Collapse
Affiliation(s)
- D Low
- Johns Hopkins School of Medicine, Baltimore, MD
| | - A Leroux
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - J Urbanek
- Johns Hopkins School of Medicine, Baltimore, MD
| | - C Crainiceanu
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
| |
Collapse
|
2
|
Martinez-Amezcua P, Wanigatunga AA, Crainiceanu C, Simonsick EM, Schrack JA. DIFFERENCES IN PHYSICAL ACTIVITY AND ITS RATE OF CHANGE BY WORK AND VOLUNTEER PARTICIPATION IN MID-TO-LATE LIFE. Innov Aging 2018. [DOI: 10.1093/geroni/igy023.240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- P Martinez-Amezcua
- Department of Epidemiology Bloomberg School of Public Health, Baltimore, Maryland, United States
| | - A A Wanigatunga
- Department of Epidemiology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Center on Aging and Health Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - C Crainiceanu
- Department of Biostatistics Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - E M Simonsick
- Intramural Research Program, National Institute on Aging, Baltimore, Maryland, USA
| | - J A Schrack
- Department of Epidemiology Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; Center on Aging and Health Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| |
Collapse
|
3
|
Aurora RN, McGuffey E, Crainiceanu C, Punjabi NM. 0467 Sleep-disordered Breathing (sdb) During Rem Sleep: Sex-specific Predictors Of Disease Evolution. Sleep 2018. [DOI: 10.1093/sleep/zsy061.466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- R N Aurora
- Johns Hopkins University, School of Medicine, Baltimore, MD
| | - E McGuffey
- United States Naval Academy, Annapolis, MD
| | - C Crainiceanu
- Johns Hopkins University, Bloomberg School of Public Healht, Baltimore, MD
| | - N M Punjabi
- Johns Hopkins University, School of Medicine, Baltimore, MD
| |
Collapse
|
4
|
Broussard JL, Aurora RN, Crainiceanu C, Punjabi NM. 0891 Race Difference In The Association Between Habitual Sleep Duration And All-cause Mortality. Sleep 2018. [DOI: 10.1093/sleep/zsy061.890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - R N Aurora
- Department of Medicine, Johns Hopkins University, Baltimore, MD
| | - C Crainiceanu
- Departments of Biostatistics, Johns Hopkins University, Baltimore, MD
| | - N M Punjabi
- Department of Medicine, Johns Hopkins University, Baltimore, MD
- Department of Epidemiology, Johns Hopkins University, Baltimore, MD
| |
Collapse
|
5
|
Shou H, Cui L, Hickie I, Lameira D, Lamers F, Zhang J, Crainiceanu C, Zipunnikov V, Merikangas KR. Dysregulation of objectively assessed 24-hour motor activity patterns as a potential marker for bipolar I disorder: results of a community-based family study. Transl Psychiatry 2017; 7:e1211. [PMID: 28892068 PMCID: PMC5611716 DOI: 10.1038/tp.2017.136] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 12/30/2016] [Indexed: 01/10/2023] Open
Abstract
There has been a growing number of studies that have employed actigraphy to investigate differences in motor activity in mood disorders. In general, these studies have shown that people with bipolar disorders (BPDs) tend to exhibit greater variability and less daytime motor activity than controls. The goal of this study was to examine whether patterns of motor activity differ in euthymic individuals across the full range of mood disorder subtypes (Bipolar I (BPI), Bipolar II (BPII) and major depression (MDD)) compared with unaffected controls in a community-based family study of mood spectrum disorders. Minute-to-minute activity counts derived from actigraphy were collected over a 2-week period for each participant. Prospective assessments of the level, timing and day-to-day variability of physical activity measures were compared across diagnostic groups after controlling for a comprehensive list of potential confounding factors. After adjusting for the effects of age, sex, body mass index (BMI) and medication use, the BPI group had lower median activity intensity levels across the second half of the day and greater variability in the afternoon compared with controls. Those with a history of BPII had increased variability during the night time compared with controls, indicating poorer sleep quality. No differences were found in the average intensity, variability or timing of activity in comparisons between other mood disorder subgroups and controls. Findings confirm evidence from previous studies that BPI may be a manifestation of a rhythm disturbance that is most prominent during the second half of the day. The present study is the largest study to date that included the full range of mood disorder subgroups in a nonclinical sample that increases the generalizability of our findings to the general community. The manifestations of activity patterns outside of acute episodes add to the accumulating evidence that dysregulation of patterns of activity may constitute a potential biomarker for BPD.
Collapse
Affiliation(s)
- H Shou
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA,Genetic Epidemiology Research Branch, Intramural Research Program, National Institute of Mental Health, Porter Neuroscience Research Center, Bethesda, MD, USA
| | - L Cui
- Genetic Epidemiology Research Branch, Intramural Research Program, National Institute of Mental Health, Porter Neuroscience Research Center, Bethesda, MD, USA
| | - I Hickie
- Brain and Mind Institute, University of Sydney, Sydney, NSW, Australia
| | - D Lameira
- Genetic Epidemiology Research Branch, Intramural Research Program, National Institute of Mental Health, Porter Neuroscience Research Center, Bethesda, MD, USA,Department of Psychology, George Mason University, Fairfax, VA, USA
| | - F Lamers
- Department of Psychiatry, EMGO Institute for Health and Care Research, VU University Medical Centre, Amsterdam, The Netherlands
| | - J Zhang
- Department of Psychiatry, Chinese University of Hong Kong, Hong Kong, PRC
| | - C Crainiceanu
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - V Zipunnikov
- Genetic Epidemiology Research Branch, Intramural Research Program, National Institute of Mental Health, Porter Neuroscience Research Center, Bethesda, MD, USA,Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - K R Merikangas
- Genetic Epidemiology Research Branch, Intramural Research Program, National Institute of Mental Health, Porter Neuroscience Research Center, Bethesda, MD, USA,Genetic Epidemiology Research Branch, Intramural Research Program, National Institute of Mental Health, Porter Neuroscience Research Center, MSC#3720, Bethesda, MD 20892, USA. E-mail:
| |
Collapse
|
6
|
Straczkiewicz M, Urbanek J, Fadel W, Crainiceanu C, Harezlak J. AUTOMATIC CAR DRIVING DETECTION USING RAW ACCELEROMETRY DATA. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.4499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - J. Urbanek
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - W. Fadel
- Biostatistics, Indiana University Fairbanks School of Public Health, Indianapolis, Indiana,
| | - C. Crainiceanu
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - J. Harezlak
- Biostatistics, Indiana University Fairbanks School of Public Health, Indianapolis, Indiana,
| |
Collapse
|
7
|
Zipunnikov V, Dey D, Leroux A, Di J, Urbanek J, Schrack J, Crainiceanu C. TOTAL PHYSICAL ACTIVITY AND ITS CIRCADIAN ALLOCATION ARE INDEPENDENT PREDICTORS OF MORTALITY. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.4500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- V. Zipunnikov
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - D. Dey
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - A. Leroux
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - J. Di
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - J. Urbanek
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - J. Schrack
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - C. Crainiceanu
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| |
Collapse
|
8
|
Harris T, Green P, Eloyan A, Zipunnikov V, Maurer M, Hung M, Crainiceanu C. USING ACCELEROMETRY TO TRACK CLINICAL TRAJECTORIES: AORTIC VALVE REPLACEMENT AS AN EXAMPLE. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.4923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- T. Harris
- Laboratory of Epidemiology and Population Sciences, NIA/Intramural Research Program, Bethesda, Maryland,
| | - P. Green
- Columbia University College of Medicine, New York, New York,
| | - A. Eloyan
- Brown University School of Public Health, Providence, Rhode Island,
| | - V. Zipunnikov
- Johns Hopkins School of Public Health,
Baltimore, Maryland
| | - M. Maurer
- Columbia University College of Medicine, New York, New York,
| | - M. Hung
- Laboratory of Epidemiology and Population Sciences, NIA/Intramural Research Program, Bethesda, Maryland,
| | - C. Crainiceanu
- Johns Hopkins School of Public Health,
Baltimore, Maryland
| |
Collapse
|
9
|
Bai J, Di C, Xiao L, Evenson K, LaCroix A, Crainiceanu C, Buchner D. AN ACTIVITY INDEX FOR RAW ACCELEROMETRY DATA AND ITS APPLICATION IN OLDER ADULTS. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.4497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J. Bai
- Department of Biostatistics, Johns Hopkins University, Baltimore, Maryland,
| | - C. Di
- Fred Hutchinson Cancer Research Center, Seattle, Washington,
| | - L. Xiao
- North Carolina State University at Raleigh, Raleigh, North Carolina,
| | - K.R. Evenson
- University of North Carolina – Chapel Hill, Chapel Hill, North Carolina,
| | - A. LaCroix
- University of California, San Diego, La Jolla, California,
| | - C. Crainiceanu
- Department of Biostatistics, Johns Hopkins University, Baltimore, Maryland,
| | - D.M. Buchner
- University of Illinois at Urbana-Champaign, Champaign, Illinois
| |
Collapse
|
10
|
Urbanek J, Harezlak J, Glynn N, Harris T, Crainiceanu C, Zipunnikov V. STRIDE VARIABILITY MEASURES DERIVED FROM WRIST AND HIP-WORN ACCELEROMETERS. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.4496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- J. Urbanek
- Johns Hopkins Bloomberg School of Public Health, Department of Biostatistics,
Baltimore, Maryland,
| | - J. Harezlak
- Indiana University School of Medicine, Department of Biostatistics,
Indianapolis, Indiana,
| | - N.W. Glynn
- University of Pittsburgh, Center for Aging and Population Health, Department of Epidemiology, Graduate School of Public Health,
Pittsburgh, Pennsylvania,
| | - T. Harris
- Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland
| | - C. Crainiceanu
- Johns Hopkins Bloomberg School of Public Health, Department of Biostatistics,
Baltimore, Maryland,
| | - V. Zipunnikov
- Johns Hopkins Bloomberg School of Public Health, Department of Biostatistics,
Baltimore, Maryland,
| |
Collapse
|
11
|
Leroux A, Schrack J, Fleg J, Simonsick E, Zipunnikov V, Studenski S, Ferrucci L, Crainiceanu C. PHYSICAL EXERTION AND ACTIVITY: AGE AND RELATIVE EFFORT IN THE BALTIMORE LONGITUDINAL STUDY OF AGING. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.4498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. Leroux
- Johns Hopkins University Bloomberg School of Public Health,
Baltimore, Maryland,
| | - J. Schrack
- Johns Hopkins University Bloomberg School of Public Health,
Baltimore, Maryland,
| | - J. Fleg
- National Heart, Lung, and Blood Institute, Bethesda, Maryland
| | | | - V. Zipunnikov
- Johns Hopkins University Bloomberg School of Public Health,
Baltimore, Maryland,
| | | | - L. Ferrucci
- National Institute on Aging, Baltimore, Maryland,
| | - C. Crainiceanu
- Johns Hopkins University Bloomberg School of Public Health,
Baltimore, Maryland,
| |
Collapse
|
12
|
Cooper R, Huang L, Hardy R, Kuh D, Crainiceanu C. OP08 Associations of contemporaneous bmi and obesity history with daily patterns of physical activity at age 60–64 years: findings from a british birth cohort study. Br J Soc Med 2015. [DOI: 10.1136/jech-2015-206256.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
13
|
Abstract
Functional principal components (FPC) analysis is widely used to decompose and express functional observations. Curve estimates implicitly condition on basis functions and other quantities derived from FPC decompositions; however these objects are unknown in practice. In this article, we propose a method for obtaining correct curve estimates by accounting for uncertainty in FPC decompositions. Additionally, pointwise and simultaneous confidence intervals that account for both model- and decomposition-based variability are constructed. Standard mixed model representations of functional expansions are used to construct curve estimates and variances conditional on a specific decomposition. Iterated expectation and variance formulas combine model-based conditional estimates across the distribution of decompositions. A bootstrap procedure is implemented to understand the uncertainty in principal component decomposition quantities. Our method compares favorably to competing approaches in simulation studies that include both densely and sparsely observed functions. We apply our method to sparse observations of CD4 cell counts and to dense white-matter tract profiles. Code for the analyses and simulations is publicly available, and our method is implemented in the R package refund on CRAN.
Collapse
Affiliation(s)
- J Goldsmith
- Department of Biostatistics, Columbia University, New York, New York 10032, USA.
| | | | | |
Collapse
|
14
|
Sweeney E, Shinohara R, Shea C, Reich D, Crainiceanu C. Lesion Incidence Estimation and Detection Using Multi-Modality Longitudinal MRIs (P03.069). Neurology 2012. [DOI: 10.1212/wnl.78.1_meetingabstracts.p03.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
15
|
Shinohara RT, Goldsmith J, Mateen FJ, Crainiceanu C, Reich DS. Predicting breakdown of the blood-brain barrier in multiple sclerosis without contrast agents. AJNR Am J Neuroradiol 2012; 33:1586-90. [PMID: 22442041 DOI: 10.3174/ajnr.a2997] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND PURPOSE Disruption of the BBB in MS is associated with the development of new lesions and clinical relapses and signifies the presence of active inflammation. It is most commonly detected as enhancement on MR imaging performed with contrast agents that are costly and occasionally toxic. We investigated whether the BBB status in white matter lesions may be indirectly ascertained via examination of features on T1- and T2-weighted images obtained before the injection of a contrast agent. MATERIALS AND METHODS We considered 93 brain MR imaging studies on 16 patients that included T1-, T2-, and T2-weighted FLAIR images and predicted voxel wise enhancement after intravenous injection of a gadolinium chelate. We then used these voxel-level predictions to determine the presence or absence of abnormal enhancement anywhere in the brain. RESULTS On a voxel-by-voxel basis, enhancement can be predicted by using contrast-free measures with an AUC of 0.83 (95% CI, 0.80-0.87). At the whole-brain level, enhancement can be predicted with an AUC of 0.72 (95% CI, 0.62-0.82). CONCLUSIONS In many cases, breakdown of the BBB in acute MS lesions may be inferred without the need to inject an MR imaging contrast agent. The inference relies on intrinsic properties of tissue damage in acute lesions. Although contrast studies are more accurate, they may sometimes be unnecessary.
Collapse
Affiliation(s)
- R T Shinohara
- Department of Biostatistics, Johns Hopkins University, Baltimore, MD 21205, USA.
| | | | | | | | | |
Collapse
|
16
|
Abstract
Capture-recapture models were developed to estimate survival using data arising from marking and monitoring wild animals over time. Variation in survival may be explained by incorporating relevant covariates. We propose nonparametric and semiparametric regression methods for estimating survival in capture-recapture models. A fully Bayesian approach using Markov chain Monte Carlo simulations was employed to estimate the model parameters. The work is illustrated by a study of Snow petrels, in which survival probabilities are expressed as nonlinear functions of a climate covariate, using data from a 40-year study on marked individuals, nesting at Petrels Island, Terre Adélie.
Collapse
Affiliation(s)
- O Gimenez
- Institute of Mathematics, Statistics and Actuarial Science, University of Kent, Canterbury, Kent CT2 7NF, UK
| | | | | | | | | |
Collapse
|
17
|
Paynter N, Crainiceanu C, Sharrett AR, Chambless L, Coresh J. 097-S: Regression Dilution in Coronary Heart Disease Risk Prediction. Am J Epidemiol 2005. [DOI: 10.1093/aje/161.supplement_1.s25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- N Paynter
- Johns Hopkins University, Baltimore, MD 21205
| | | | | | - L Chambless
- Johns Hopkins University, Baltimore, MD 21205
| | - J Coresh
- Johns Hopkins University, Baltimore, MD 21205
| |
Collapse
|
18
|
van Schaik G, Schukken YH, Crainiceanu C, Muskens J, VanLeeuwen JA. Prevalence estimates for paratuberculosis adjusted for test variability using Bayesian analysis. Prev Vet Med 2003; 60:281-95. [PMID: 12941553 DOI: 10.1016/s0167-5877(03)00157-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ELISA tests that are available to detect an infection with Mycobacterium avium subsp. paratuberculosis (MAP) have a limited validity expressed as the sensitivity (Se) and specificity (Sp). In many studies, the Se and Sp of the tests are treated as constants and this will result in an underestimation of the variability of the true prevalence (TP). Bayesian inference provided a natural framework for using information on the test variability (i.e., the uncertainty) in the estimates of test Se and Sp when estimating the TP. Data from two prevalence studies for MAP using an ELISA in several regions in two locations were available for the analyses. In location 1, all cattle of at least 3 years of age were sampled in approximately 90 randomly sampled herds in each of the four regions of the country. In location 2, in 30 randomly sampled herds in each of three regions, approximately 30 randomly selected cows were sampled. Information about the unknown test Se and Sp and MAP prevalence was incorporated into a Bayesian model by joint prior probability distributions. Posterior estimates were obtained by combining the actual likelihood with the prior distributions using Bayes' formula. The corrected cow-level TP (proportion of infected cows in a herd) was low, 5.8 and 3.6% in locations 1 and 2, respectively. Certain regions within a location differed significantly in herd-level TP (proportion of infected herds). The herd-level TP was 54.3% in location 1 (95% credible interval (CI) 46.1, 63.3%) and 32.9% in location 2 (95% CI: 14.4, 73.3%). The variation in the herd-level TP estimate for location 2 was more than three times as large as the variation in location 1 mainly because of the relatively small number of investigated herds in location 2. In future prevalence studies for MAP, sample size calculations should be based on a very low cow-level prevalence. Approximately 50 and 90% of the herds in the current study had an estimated cow-level TP below 4 and 10%, respectively.
Collapse
Affiliation(s)
- G van Schaik
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
| | | | | | | | | |
Collapse
|