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1.  Construct Validity of the SF-12 among American Indian and Alaska Native People Using Two Known Scoring Methods 
Journal of health care for the poor and underserved  2012;23(3):10.1353/hpu.2012.0092.
This study evaluated the construct validity of the 12-Item Short Form Survey Instrument (SF-12) in a cohort of American Indian and Alaska Native (AIAN) people. We evaluated two scoring methods to determine their utility in this population.
Participants (N=11,127) were aged 18 and older, self-identified as AIAN, and had complete SF-12 interview data. Physical and mental health summary scores were calculated using traditional SF-12 (PCS12 and MCS12) and RAND-12 (PHC and MHC) scoring methods.
Women scored lower than men on the PHC, PCS12, MHC, and MCS12, as did those with more medical conditions versus none. Those aged 55 and older scored lower on the PHC and PCS12 than younger people. There was no difference in the mean MCS12 score by age and for those 31–55 and aged older than 55 for the MHC.
This study demonstrates the construct validity of the PCS12/MCS12 and PHC/MHC in a cohort of AIAN people.
PMCID: PMC3831375  PMID: 24212164
SF12; RAND-12; North American Indians; health-related quality of life
2.  Examining the challenges of family recruitment to behavioral intervention trials: factors associated with participation and enrollment in a multi-state colonoscopy intervention trial 
Trials  2013;14:116.
Colonoscopy is one of the most effective methods of cancer prevention and detection, particularly for individuals with familial risk. Recruitment of family members to behavioral intervention trials remains uniquely challenging, owing to the intensive process required to identify and contact them. Recruiting at-risk family members involves contacting the original cancer cases and asking them to provide information about their at-risk relatives, who must then be contacted for study enrollment. Though this recruitment strategy is common in family trials, few studies have compared influences of patient and relative participation to nonparticipation. Furthermore, although use of cancer registries to identify initial cases has increased, to our knowledge no study has examined the relationship between registries and family recruitment outcomes.
This study assessed predictors of case participation and relative enrollment in a recruitment process that utilized state cancer registries. Participation characteristics were analyzed with separate multivariable logistic regressions in three stages: (1) cancer registry-contacted colorectal cancer (CRC) cases who agreed to study contact; (2) study-contacted CRC cases who provided at-risk relative information; and (3) at-risk relatives contacted for intervention participation.
Cancer registry source was predictive of participation for both CRC cases and relatives, though relative associations (odds ratios) varied across registries. Cases were less likely to participate if they were Hispanic or nonwhite, and were more likely to participate if they were female or younger than 50 at cancer diagnosis. At-risk relatives were more likely to participate if they were from Utah, if another family member was also participating in the study, or if they had previously had a colonoscopy. The number of eligible cases who had to be contacted to enroll one eligible relative varied widely by registry, from 7 to 81.
Family recruitment utilizing cancer registry-identified cancer cases is feasible, but highly dependent on both the strategies and protocols of those who are recruiting and on participant characteristics such as sex, race, or geography. Devising comprehensive recruitment protocols that specifically target those less likely to enroll may help future research meet recruitment goals.
Trial registration
Family Colorectal Cancer Awareness and Risk Education Project NCT01274143.
PMCID: PMC3691526  PMID: 23782890
Cancer; Colorectal; Patient selection; Recruitment
3.  Physical Activity Patterns of American Indian and Alaskan Native People Living in Alaska and the Southwestern United States 
Assessment of self reported physical activity (PA) and effects on health measures.
Cross-sectional analysis of baseline data from a cohort study.
Education and Research Towards Health study participants from Alaska and the Southwestern United States enrolled from 2004 to 2007.
Total of 10,372 American Indian and Alaskan Native people (AI/AN) of at least 18 years.
Participants completed computer-assisted, self-administered questionnaires, and anthropometric and health measurements were taken of each participant.
Analysis of variance, χ2 tests, and multiple linear regressions were used.
Almost 23% of participants reported less than 30 minutes per week of moderate or vigorous activities. Half (49%) reported no vigorous activities. Characteristics associated with more time spent performing vigorous activity were male gender, age less than 40 years, higher income and education levels, and living in a rural area. Almost 70% of Alaskan participants and 36% of Southwest participants engaged in wild food-harvesting activities. Participants with higher levels of activity had significantly better clinical characteristics (high-density lipoprotein cholesterol, triglycerides, body mass index, and waist circumference).
AI/AS people engage in many different physical activities, including traditional harvesting activities. Women had lower levels of PA than men, and participation in vigorous PA was associated with better clinical characteristics. These data can he used to guide health promotion efforts in AI/AN populations.
PMCID: PMC3436119  PMID: 19601478
Alaskan Native; American Indian; Physical Activity; Prevention Research; Manuscript format: research; Research purpose: descriptive; Study design: nonexperimental; Outcome measure: behavioral, biometric; Setting: local community; Health focus: fitness/physical activity; Strategy: culture change; Target population age: adults; Target population circumstances: education/income level, geographic location, race/ethnicity
4.  Identifying associations between pig pathologies using a multi-dimensional machine learning methodology 
Abattoir detected pathologies are of crucial importance to both pig production and food safety. Usually, more than one pathology coexist in a pig herd although it often remains unknown how these different pathologies interrelate to each other. Identification of the associations between different pathologies may facilitate an improved understanding of their underlying biological linkage, and support the veterinarians in encouraging control strategies aimed at reducing the prevalence of not just one, but two or more conditions simultaneously.
Multi-dimensional machine learning methodology was used to identify associations between ten typical pathologies in 6485 batches of slaughtered finishing pigs, assisting the comprehension of their biological association. Pathologies potentially associated with septicaemia (e.g. pericarditis, peritonitis) appear interrelated, suggesting on-going bacterial challenges by pathogens such as Haemophilus parasuis and Streptococcus suis. Furthermore, hepatic scarring appears interrelated with both milk spot livers (Ascaris suum) and bacteria-related pathologies, suggesting a potential multi-pathogen nature for this pathology.
The application of novel multi-dimensional machine learning methodology provided new insights into how typical pig pathologies are potentially interrelated at batch level. The methodology presented is a powerful exploratory tool to generate hypotheses, applicable to a wide range of studies in veterinary research.
PMCID: PMC3483212  PMID: 22937883
5.  The Weaker Sex? The Propensity for Male-Biased Piglet Mortality 
PLoS ONE  2012;7(1):e30318.
For the most part solutions to farm animal welfare issues, such as piglet mortality, are likely to lie within the scientific disciplines of environmental design and genetic selection, however understanding the ecological basis of some of the complex dynamics observed between parent and offspring could make a valuable contribution. One interesting, and often discussed, aspect of mortality is the propensity for it to be sex-biased. This study investigated whether known physiological and behavioural indicators of piglet survival differed between the sexes and whether life history strategies (often reported in wild or feral populations) relating to parental investment were being displayed in a domestic population of pigs. Sex ratio (proportion of males (males/males+females)) at birth was 0.54 and sex allocation (maternal investment measured as piglet birth weight/litter weight) was statistically significantly male-biased at 0.55 (t35 = 2.51 P = 0.017), suggesting that sows invested more in sons than daughters during gestation. Despite this investment in birth weight, a known survival indicator, total pre-weaning male mortality was statistically significantly higher than female mortality (12% vs. 7% respectively z = 2.06 P = 0.040). Males tended to suffer from crushing by the sow more than females and statistically significantly more males died from disease-related causes. Although males were born on average heavier, with higher body mass index and ponderal index, these differences were not sustained. In addition male piglets showed impaired thermoregulation compared to females. These results suggest male-biased mortality exists despite greater initial maternal investment, and therefore reflects the greater susceptibility of this sex to causal mortality factors. Life history strategies are being displayed by a domestic population of pigs with sows in this study displaying a form of parental optimism by allocating greater resources at birth to males and providing an over-supply of this more vulnerable sex in expectation of sex-biased mortality.
PMCID: PMC3260262  PMID: 22272334
6.  Validation of a Dietary History Questionnaire for American Indian and Alaska Native People 
Ethnicity & disease  2010;20(4):429-436.
We assessed reliability and relative validity of a self-administered computer-assisted dietary history questionnaire (DHQ) for use in a prospective study of diet, lifestyle, and chronic disease in American Indians in the Dakotas and Southwestern US and Alaska Native people.
Reliability was assessed by one-month test-retest of the dietary history questionnaire. Validity was assessed by comparison of the weighted average of up to 12 monthly 24-hour recalls collected prospectively and a dietary history questionnaire completed in the 13th month.
Participants were recruited at the baseline visit of the Education and Research Toward Health Study in Alaska, the Northern Plains and the Dakotas.
Reliability (Pearson correlation) of the DHQ ranged from r= 0.43 for vitamin A density to r=0.90 for energy intake. The association of nutrient and food estimates assessed by 24-hour recalls and the DHQ completed at the end of the year reflected no bias towards recent intake. Macronutrients expressed as density (nutrients per 1000 calories) did appear to be valid (r 0.50–0.71) as did several micronutrients (range r=.22 to 0.59), fiber (r=0.51), and servings of red meat (r=0.67). However, the DHQ overestimated intake and gross amounts of nutrients were not strongly associated with the weighted average of the 24-hour recalls.
The DHQ developed for estimation of dietary intake in American Indians and Native people in Alaska is reliable. Estimates of nutrient density appeared to have acceptable relative validity for use in epidemiologic studies.
PMCID: PMC3234169  PMID: 21305833
Dietary Intake; American Indians; Alaska Natives; Diet Measurement
7.  Associations Among Body Mass Index, Waist Circumference, and Health Indicators in American Indian and Alaska Native Adults 
Little is known about obesity-related health issues among American Indian and Alaska Native (AIAN) populations.
A large cohort of AIAN people was assembled to evaluate factors associated with health.
The study was conducted in Alaska and on the Navajo Nation.
A total of 11,293 AIAN people were included.
We present data for body mass index (BMI, kg/m2) and waist circumference (cm) to evaluate obesity-related health factors.
Overall, 32.4% of the population were overweight (BMI 25–29.9 kg/m2), 47.1% were obese (BMI ≥ 30 kg/m2), and 21.4% were very obese (BMI, ≥ 35 kg/m2). A waist circumference greater than 102 cm for men and greater than 88 cm for women was observed for 41.7% of men and 78.3% of women. Obese people were more likely to perceive their health as fair/poor than nonobese participants (prevalence ratio [PR]), 1.91; 95% CI, 1.71–2.14). Participants younger than 30 years were three times more likely to perceive their health as being fair or poor when their BMI results were 35 or greater compared with those whose BMI results were less than 25 kg/m2. A larger BMI was associated with having multiple medical conditions, fewer hours of vigorous activity, and more hours of television watching.
Given the high rates of obesity in AIAN populations and the association of obesity with other health conditions, it is important to reduce obesity among AIAN people.
PMCID: PMC2925498  PMID: 20232606
American Indian; Alaska Native; Body Mass Index; Obesity; Physical Activity
8.  Physical Activity and Breast Cancer Risk Among Women in the Southwestern United States 
Annals of epidemiology  2007;17(5):342-353.
Physical activity may influence breast cancer risk through multiple mechanisms and at different periods in life. In this study we evaluate breast cancer risk associated with total and vigorous physical activity at ages 15, 30, and 50 years and the referent year prior to diagnosis/selection. Participants were non-Hispanic white (NHW) (1527 cases and 1601 control subjects) and Hispanic/American Indian (HAI) (798 cases and 924 controls) women. Both total and vigorous activity reduced risk of breast cancer in a dose-response manner. Among premenopausal women, only high total metabolic equivalent of the task (MET) hours of activity during the referent year was associated with reduced breast cancer risk in NHW women (odds ratio [OR] 0.62; 95% confidence interval [CI] 0.43, 0.91). Among postmenopausal women, physical activity had the greatest influence among women not recently exposed to hormones. Among these women, high total lifetime activity reduced risk of breast cancer for both NHW (OR 0.60; 95% CI 0.36, 1.02; p trend 0.01) and HAI women (OR 0.52; 95% CI 0.23, 1.16; p trend 0.07). Additionally, high total MET hours of activity at age 30 years (OR 0.56; 95% CI 0.37, 0.85) and at age 15 years (OR 0.57; 95% CI 0.38, 0.88) reduced breast cancer risk among postmenopausal NHW women not recently exposed to hormones. Among HAI women, more recent activity performed during the referent year and at age 50 appeared to have the greatest influence on breast cancer risk. Among postmenopausal NHW women. there was a significant interaction between physical activity and hormone replacement therapy (p value, 0.01), while among postmenopausal HAI women, physical activity interacted with body mass index (p value, 0.04). These data suggest that physical activity is important in reducing risk of breast cancer in both NHW and HAI women.
PMCID: PMC2925501  PMID: 17462544
BMI; Breast Cancer; Physical Activity; Hispanic; Hormones
9.  Factors associated with response to a follow-up postal questionnaire in a cohort of American Indians 
Preventive medicine  2009;48(6):596-599.
The aim of the study was to collect pilot data on response rates to a follow-up postal questionnaire in a cohort of American Indians living in the Southwestern United States. We tested the effect of questionnaire length on response.
Cohort members were American Indian adults aged 18 and over who completed the baseline study visit. Study participants (N=1587), cohort members who completed the baseline study visit during the first year of enrollment, were randomized into two groups to receive either an 18-page or 3-page follow-up postal questionnaire. Data were collected between October 2005 and March 2006.
The response rates after two questionnaire mailings and a reminder postcard were significantly higher for the short versus the long (56.2%, 48.1% p=<0.01) questionnaire. Being female and being aged 50 or older were associated with returning a completed questionnaire. A reminder postcard and second mailing improved response by 11.7% and 13.4% respectively.
These results show that a postal questionnaire can be used in a cohort of American Indians living in the Southwest, but suggest that questionnaires should be short and repeat mailings are needed.
PMCID: PMC2925509  PMID: 19285524
Mesh heading key words; Epidemiologic methods; Follow-up studies; Data collection; Indians; North American
10.  Arthritis Prevalence and Associations in American Indian and Alaska Native People 
Arthritis and rheumatism  2008;59(8):1128-1136.
To investigate the prevalence of arthritis and associations with arthritis in American Indian and Alaska Native populations.
Data on self-reported, doctor-diagnosed arthritis from the baseline visit of 9,968 American Indian and Alaska Native adults from Alaska and the Southwest US were included. The prevalence of arthritis and univariate and multivariate associations between arthritis and demographic characteristics, health-related factors, and treatment are described.
The prevalence of self-reported arthritis increased with age. The age-sex adjusted prevalence was high in Alaska (26.1%) and low in the Southwest US (16.5%) as compared with the US population (21.5%). In both centers, arthritis was associated with age, lack of employment, chronic medical conditions, and poorer self-reported overall health. Arthritis was associated with female sex in Alaska only, whereas education, marital status, and urban residency were associated with arthritis in the Southwest US. In both centers, self-reported physical health measured by the Short Form 12 Health Survey was lower in people with arthritis, and mental health was not associated with arthritis. More frequent use of antiinflammatory medications was reported with arthritis in both centers, but increased use of traditional medicine and healers were associated with arthritis only in Alaska.
Compared with US rates, the prevalence of self-reported arthritis was higher among Alaska Native people and lower in a Southwest American Indian population. Some factors associated with arthritis differ between the 2 populations.
PMCID: PMC2925516  PMID: 18668615
11.  Family Health History and Health Behaviors in Alaska Native and American Indian People 
Family history of diseases among American Indian and Alaska Native (AIAN) people may influence health.
We examine the prevalence of family health history among a cohort of AIAN people (n= 10,374) enrolled in the Education and Research Towards Health (EARTH) Study. We evaluate the association between having a positive family history and health behaviors to determine if those reporting a family history were more likely to report lifestyles that put them at risk of developing these health conditions.
Among participants, 17.7% reported not knowing their family history and 23.5% preferred not to answer the family history component of the questionnaire. Eight percent of participants reported a family history of colorectal cancer, 7.9% a family history of breast cancer, 25.8% a family history of heart attack, and 46.7% a family history of diabetes. Obesity, physical activity, cholesterol, and perceived health were associated with family history.
Individuals with a family history of diseases may have lifestyles that influence their disease risk.
PMCID: PMC2925532  PMID: 19648697
Family history; cancer; heart disease; diabetes; diet; American Indian; Alaska Native; health; stroke
12.  A comparison of colon and rectal somatic DNA alterations 
Diseases of the colon and rectum  2009;52(7):1304-1311.
Background and Aims
Differences in acquired mutations in colon and rectal tumors may account for differences in risk factors. In this study, we examined similarities and differences in somatic alterations in colon and rectal tumors.
Cases were identified from two large population-based case-control studies of colon cancer and rectal cancer. We sequenced exons 5 to 8 of the p53 gene and codons 12 and 13 of the Ki-ras gene to identify tumor mutations. Micro-satellite instability was determined based on BAT26 and TGFβRII analysis; CpG Island Methylator Phenotype was determined based on having two or more of the following markers methylated p16, MLH1, MINT1, MINT2, and MINT31.
p53 mutations were observed in 39.7 percent of proximal, 51.0 percent of distal, and 46.6 percent of rectal tumors; Ki-ras mutations were observed in 36.0 percent of proximal, 26.9 percent of distal and 30.5 percent of rectal tumors. While 40.9 percent of proximal tumors were considered CpG Island Methylator Phenotype positive (having 2 or more of 5 markers methylated), only 12.9 percent of distal and 11.9 percent of rectal tumors were CpG Island Methylator Phenotype positive. Likewise, microsatellite instability was observed in 23.7 percent of proximal and only 3.8 percent of distal and 2.0 percent of rectal tumors. Over 50 percent of distal colon or rectal tumors had only one acquired mutation, while only 35.1 percent of proximal tumors had one mutation. The most common single mutation for colon and rectal tumors was p53 followed by Ki-ras mutations.
Our findings suggest unique mutational pathways are involved in the development of most colorectal tumors. Proximal colon cancers are more likely to have microsatellite instability, CpG Island Methylator Phenotype, and Ki-ras mutations, while rectal and distal colon tumors are more likely to have a p53 mutation than proximal colon tumors. Overall, rectal and distal colon tumors share similar mutational frequencies than do proximal colon tumors.
PMCID: PMC2718791  PMID: 19571709
Colon cancer; Rectal cancer; p53; Ki-ras; CpG Island Methylator Phenotype; microsatellite instability; Distal; Proximal
13.  A computer-assisted data collection system for use in a multicenter study of American Indians and Alaska Natives: SCAPES 
We describe a computer-assisted data collection system developed for a multicenter cohort study of American Indian and Alaska Natives. The Study Computer-Assisted Participant Evaluation System or SCAPES is built around a central database server that controls a small private network with touch screen workstations. SCAPES encompasses the self-administered questionnaires, the keyboard-based stations for interviewer-administered questionnaires, a system for inputting medical measurements, and administrative tasks such as data exporting, backup and management. Elements of SCAPES hardware/network design, data storage, programming language, software choices, questionnaire programming including the programming of questionnaires administered using audio computer-assisted self interviewing (ACASI), and participant identification/data security system are presented. Unique features of SCAPES are that data are promptly made available to participants in the form of health feedback; data can be quickly summarized for tribes for health monitoring and planning at the community level; and data are available to study investigators for analyses and scientific evaluation.
PMCID: PMC2374761  PMID: 18207604
14.  Prevalence and predictors of cancer screening among American Indian and Alaska native people: the EARTH study 
Cancer causes & control : CCC  2008;19(7):725-737.
The purpose of this study was to examine the prevalence rates for cervical, breast, and colorectal cancer screening among American Indian and Alaska Native people living in Alaska and in the Southwest US, and to investigate predictive factors associated with receiving each of the cancer screening tests.
We used the Education and Research Towards Health (EARTH) Study to measure self-reported cancer screening prevalence rates among 11,358 study participants enrolled in 2004–2007. We used prevalence odds ratios to examine demographic, lifestyle and medical factors associated with receiving age- and sex-appropriate cancer screening tests.
The prevalence rates of all the screening tests were higher in Alaska than in the Southwest. Pap test in the past 3 years was reported by 75.1% of women in Alaska and 64.6% of women in the Southwest. Mammography in the past 2 years was reported by 64.6% of women aged 40 years and older in Alaska and 44.0% of those in the Southwest. Colonoscopy or sigmoidoscopy in the past 5 years was reported by 41.1% of study participants aged 50 years and older in Alaska and by 11.7% of those in the Southwest US. Multivariate analysis found that location (Alaska versus the Southwest), higher educational status, income and the presence of one or more chronic medical condition predicted each of the three screening tests. Additional predictors of Pap test were age (women aged 25–39 years more likely to be screened than older or younger women), marital status (ever married more likely to be screened), and language spoken at home (speakers of American Indian Alaska Native language only less likely to be screened). Additional predictors of mammography were age (women aged 50 years and older were more likely to be screened than those aged 40–49 years), positive family history of breast cancer, use of smokeless tobacco (never users more likely to be screened), and urban/rural residency (urban residents more likely to be screened). Additional predictors of colonoscopy/sigmoidoscopy were age (men and women aged 60 years and older slightly more likely to be screened than those aged 50–59 years), family history of any cancer, family history of colorectal cancer, former smoking, language spoken at home (speakers of American Indian Alaska Native language less likely to be screened), and urban/rural residence (urban residents more likely to be screened).
Programs to improve screening among American Indian and Alaska Native people should include efforts to reach individuals of lower socioeconomic status and who do not have regular contact with the medical care system. Special attention should be made to identify and provide needed services to those who live in rural areas, and to those living in the Southwest US.
PMCID: PMC2574651  PMID: 18307048
Papanicolaou test; Mammography; Colon cancer screening; American Indian; Alaska Native
15.  Active and passive smoking, IL6, ESR1, and breast cancer risk 
We evaluated the association between smoking and risk of breast cancer in non-Hispanic white (NHW) and Hispanic or American Indian (HAI) women living in the Southwestern United States. Data on lifetime exposure to active and passive smoke data were available from 1527 NHW cases and 1601 NHW controls; 798 HAI cases and 924 HAI controls. Interleukin 6 (IL6) and Estrogen Receptor alpha (ESR1) polymorphisms were assessed in conjunction with smoking. Pack-years of smoking (≥15) were associated with increased risk of pre-menopausal breast cancer among NHW women (OR 1.6, 95% CI 1.1–2. 4). Passive smoke increased risk of pre-menopausal breast cancer for HAI women (OR 1.9, 95% CI 1.1–3.1 everyone; OR 2.3, 95% CI 1.2–4.5 nonsmokers). HAI pre-menopausal women who were exposed to 10+ h of passive smoke per week and had the rs2069832 IL6 GG genotype had over a fourfold increased risk of breast cancer (OR 4.4, 95% CI 1.5–12.8; P for interaction 0.01). Those with the ESR1 Xba1 AA genotype had a threefold increased risk of breast cancer if they smoked ≥15 pack-years relative to non-smokers (P interaction 0.01). These data suggest that breast cancer risk is associated with active and passive smoking.
PMCID: PMC2532584  PMID: 17594514
Breast cancer; Cigarette smoke; ESR1; IL6; Hispanic; Passive smoking
16.  Development, Implementation, and Evaluation of a Computerized Self-Administered Diet History Questionnaire for Use in Studies of American Indian and Alaskan Native People 
Collection of dietary intake in epidemiologic studies involves using methods that are comprehensive yet appropriate for the population being studied. Here we describe a diet history questionnaire (DHQ) that was developed using an audio self-administered computer-assisted interview technique. The DHQ was developed for use in a cohort of American Indians and Alaskan Natives with tribal input and area-specific modules to incorporate local food availability. The DHQ includes 54 main food group questions, specific food items within the main food group, and food preparation and general eating practice questions. The questionnaire was programmed to be self-administered using a computer with a touch screen. The average time for the first 6,604 participants to complete the questionnaire was 36 minutes. Almost 100% of participants had complete DHQ data and the average number of food items selected was 70. The methods developed for collection of dietary data appear to be appropriate for the targeted population and may have usefulness for other populations where collecting dietary data in a self-administered format is desirable.
PMCID: PMC2474673  PMID: 18155994
17.  Expert opinion as 'validation' of risk assessment applied to calf welfare 
Recently, a Risk Assessment methodology was applied to animal welfare issues in a report of the European Food Safety Authority (EFSA) on intensively housed calves.
Because this is a new and potentially influential approach to derive conclusions on animal welfare issues, a so-called semantic-modelling type 'validation' study was conducted by asking expert scientists, who had been involved or quoted in the report, to give welfare scores for housing systems and for welfare hazards.
Kendall's coefficient of concordance among experts (n = 24) was highly significant (P < 0.001), but low (0.29 and 0.18 for housing systems and hazards respectively). Overall correlations with EFSA scores were significant only for experts with a veterinary or mixed (veterinary and applied ethological) background. Significant differences in welfare scores were found between housing systems, between hazards, and between experts with different backgrounds. For example, veterinarians gave higher overall welfare scores for housing systems than ethologists did, probably reflecting a difference in their perception of animal welfare.
Systems with the lowest scores were veal calves kept individually in so-called "baby boxes" (veal crates) or in small groups, and feedlots. A suckler herd on pasture was rated as the best for calf welfare. The main hazards were related to underfeeding, inadequate colostrum intake, poor stockperson education, insufficient space, inadequate roughage, iron deficiency, inadequate ventilation, poor floor conditions and no bedding. Points for improvement of the Risk Assessment applied to animal welfare include linking information, reporting uncertainty and transparency about underlying values.
The study provides novel information on expert opinion in relation to calf welfare and shows that Risk Assessment applied to animal welfare can benefit from a semantic modelling approach.
PMCID: PMC2483281  PMID: 18625048
18.  Changing population characteristics, effect-measure modification, and cancer risk factor identification 
Epidemiologic studies have identified a number of lifestyle factors, e.g. diet, obesity, and use of certain medications, which affect risk of colon cancer. However, the magnitude and significance of risk factor-disease associations differ among studies. We propose that population trends of changing prevalence of risk factors explains some of the variability between studies when factors that change prevalence also modify the effect of other risk factors. We used data collected from population-based control who were selected as study participants for two time periods, 1991–1994 and 1997–2000, along with data from the literature, to examine changes in the population prevalence of aspirin and non-steroidal anti-inflammatory medication (NSAID) use, obesity, and hormone replacement therapy (HRT) over time. Data from a population-based colon cancer case-control study were used to estimate effect-measurement modification among these factors. Sizeable changes in aspirin use, HRT use, and the proportion of the population that is obese were observed between the 1980s and 2000. Use of NSAIDs interacted with BMI and HRT; HRT use interacted with body mass index (BMI). We estimate that as the prevalence of NSAIDs use changed from 10% to almost 50%, the colon cancer relative risk associated with BMI >30 would change from 1.3 to 1.9 because of the modifying effect of NSAIDs. Similarly, the relative risk estimated for BMI would increase as the prevalence of use of HRT among post-menopausal women increased. In conclusion, as population characteristics change over time, these changes may have an influence on relative risk estimates for colon cancer for other exposures because of effect-measure modification. The impact of population changes on comparability between epidemiologic studies can be kept to a minimum if investigators assess exposure-disease associations within strata of other exposures, and present results in a manner that allows comparisons across studies. Effect-measure modification is an important component of data analysis that should be evaluated to obtain a complete understanding of disease etiology.
PMCID: PMC2098767  PMID: 17908309

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