Establishing Digital Biomarkers for Occupational Health Assessment in Commercial Salmon Fishermen: Protocol for a Mixed-Methods Study.

BACKGROUND: Commercial salmon fishing in Alaska is one of the most dangerous occupations in the United States. Between 1992 and 2008, the average annual industry mortality rate was 128 deaths per 100,000 workers, and despite an increase in industry regulations, there has not been a significant decrease in mortality rate since 2000. Unpredictable fishing openings and fierce competition for limited resources result in periods of intense sleep deprivation and physical strain during the short commercial salmon season in Alaska. OBJECTIVE: We hypothesize that the combined effect of sleep deprivation, intense physical workload, and significant short-term chronic stress may be deleterious to health in both the short- and long-term among commercial salmon drift gillnet fishermen in Alaska. The objective of this protocol is to determine the feasibility of the study design to test this hypothesis. METHODS: The study design uses mixed methods and includes biometric monitoring consisting of heart rate variability, respiration, and movement data collected via a personal, wearable biometric device. Additional methods include observational data on activity, including duration and quality of sleep, weather, catch, and financial gain, as well as the collection of salivary cortisol. As such, the study will provide a holistic assessment of individual stress on multiple simultaneous timescales: immediately and continuously through the personal wearable biometric device, on the minute-hour level through the multiple daily collections of salivary cortisol, and by the hour-day through the use of participant and environment observational data. RESULTS: Data collection was initiated in July 2017 and will extend through August 2019. Initial data collection has indicated that the methods outlined in this protocol are feasible and allow for effective collection of qualitative and quantitative data related to the psychological and physiological impact of Alaska commercial salmon fishing. CONCLUSIONS: We anticipate that the use of a biometric device will be crucial in establishing measures of stress and physical activity within a population and environment uniquely challenged by physical isolation, strong weather patterns, and the potential for significant financial gain by fishermen. The potential exists for individuals engaged long-term in the fishing industry, through repeated and extended exposure to periods of intense sleep deprivation and chronic stress, to be at increased risk of cardiovascular disease. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/10215.

The effects of market integration on childhood growth and nutritional status: the dual burden of under- and over-nutrition in the Northern Ecuadorian Amazon.

OBJECTIVES: Market integration is an important source of cultural change exposing indigenous populations to epidemiologic and nutrition transitions. As children and adolescents are biologically sensitive to the health effects of market integration, we examine community variation of anthropometric indicators of nutritional status and growth among a cross-cultural sample of Kichwa, Shuar, Huaorani, and Cofán indigenous groups in the northern Ecuadorian Amazon. METHODS: We measured height, weight, body mass index (BMI), upper arm circumference, and triceps skinfolds of 186 children and adolescents aged 2 to 18 years from seven communities. Anthropometric z-scores were calculated based on the National Health and Nutritional Examination Survey. Comparisons were made with this US reference group, along with between community differences to contextually explore the impacts of varying degrees of market integration. RESULTS: We found a high prevalence of stunting in both boys (40%) and girls (34%). Adiposity increased with age and 40% of girls between 15 and 18 years old were overweight. There were large sex differences in body composition with higher BMI, arm circumference, and triceps skinfolds in adolescent girls. The Kichwa demonstrated the poorest growth outcomes and nutritional stress followed by the Huaorani and Shuar; yet distinctions in under- and over-nutrition were evident within groups. CONCLUSION: Market integration is a major factor influencing the developmental and lifestyle mismatch associated with the epidemiologic and nutrition transition in general, and the dual burden pattern of high rates of stunting yet adequate to above average short-term nutritional status indicators found among indigenous Amazonian populations.

Reduced fat oxidation and obesity risks among the Buryat of Southern Siberia.

Over the last 20 years, obesity and associated metabolic diseases have emerged as major global health problems. Among urbanizing populations of developing regions of the world, childhood undernutrition often coexists with adult overnutrition, a phenomenon known as the "dual nutritional burden". A recent work (Frisancho 2003: Am J Hum Biol 15:522-532) suggests that linear growth stunting in early childhood may contribute to adult obesity by reducing the body's ability to oxidize fat. We test central aspects of this model drawing on data from 112 adult Buryat herders (53 males; 59 females) from Southern Siberia. The results are consistent with the predictions of the model, but only for women. Shorter Buryat women (height-for-age Z-scores < or = -1) have significantly lower fasting fat oxidation levels compared to their taller counterparts. Shorter women are also significantly heavier and fatter, and have higher serum lipid levels. Among all Buryat women, reduced fat oxidation is significantly correlated with percent body fatness, serum triglyceride levels, and serum leptin levels, after controlling for relevant covariates. Additionally, Buryat women with high dietary fat intakes and low fat oxidation are significantly fatter and have higher lipid and leptin levels than those with low fat intakes and high fat oxidation. These results suggest that developmental changes in fat oxidation may play a role in the origins of obesity among populations with high rates of linear growth stunting. Further longitudinal research is necessary to elucidate the pathways through which early-life undernutrition may increase risks for adulthood obesity and cardiovascular disease.

Coalescent simulations of Yakut mtDNA variation suggest small founding population.

The Yakuts are a Turkic-speaking population from northeastern Siberia who are believed to have originated from ancient Turkic populations in South Siberia, based on archaeological and ethnohistorical evidence. In order to better understand Yakut origins, we modeled 25 demographic scenarios and tested by coalescent simulation whether any are consistent with the patterns of mtDNA diversity observed in present-day Yakuts. The models consist of either two simulated demes that represent Yakuts and a South Siberian ancestral population, or three demes that also include a regional Northeast Siberian population that served as a source of local gene flow into the Yakut deme. The model that produced the best fit to the observed data defined a founder group with an effective female population size of only 150 individuals that migrated northwards approximately 1,000 years BP and who experienced significant admixture with neighboring populations in Northeastern Siberia. These simulation results indicate a pronounced founder effect that was primarily kin-structured and reconcile reported discrepancies between Yakut mtDNA and Y chromosome diversity levels.

Lifestyle incongruity, stress and immune function in indigenous Siberians: the health impacts of rapid social and economic change.

The purpose of this study was to investigate the impact of economic and cultural change on immune function and psychosocial stress in an indigenous Siberian population. We examined Epstein-Barr virus antibodies (EBV), an indirect biomarker of cell-mediated immune function, in venous whole blood samples collected from 143 Yakut (Sakha) herders (45 men and 98 women) in six communities using a cross-sectional study design. We modeled economic change through the analysis of lifestyle incongruity (LI), calculated as the disparity between socioeconomic status and material lifestyle, computed with two orthogonal scales: market and subsistence lifestyle. EBV antibody level was significantly negatively associated with both a market and a subsistence lifestyle, indicating higher cell-mediated immune function associated with higher material lifestyle scores. In contrast, LI was significantly positively associated with EBV antibodies indicating lower immune function, and suggesting higher psychosocial stress, among individuals with economic status in excess of material lifestyle. Individuals with lower incongruity scores (i.e., economic status at parity with material resources, or with material resources in excess of economic status) had significantly lower EBV antibodies. The findings suggest significant health impacts of changes in material well-being and shifting status and prestige markers on health during the transition to a market economy in Siberia. The findings also suggest that relative, as opposed to absolute, level of economic status or material wealth is more strongly related to stress in the Siberian context.

The influence of basal metabolic rate on blood pressure among indigenous Siberians.

Hypertension is an important global health issue and is currently increasing at a rapid pace in most industrializing nations. Although a number of risk factors have been linked with the development of hypertension, including obesity, high dietary sodium, and chronic psychosocial stress, these factors cannot fully explain the variation in blood pressure and hypertension rates that occurs within and between populations. The present study uses data collected on adults from three indigenous Siberian populations (Evenki, Buryat, and Yakut [Sakha]) to test the hypothesis of Luke et al. (Hypertension 43 (2004) 555-560) that basal metabolic rate (BMR) and blood pressure are positively associated independent of body size. When adjusted for body size and composition, as well as potentially confounding variables such as age, smoking status, ethnicity, and degree of urbanization, BMR was positively correlated with systolic blood pressure (SBP; P < 0.01) and pulse pressure (PP; P < 0.01); BMR showed a trend with diastolic blood pressure (DBP; P = 0.08). Thus, higher BMR is associated with higher SBP and PP; this is opposite the well-documented inverse relationship between physical activity and blood pressure. If the influence of BMR on blood pressure is confirmed, the systematically elevated BMRs of indigenous Siberians may help explain the relatively high blood pressures and hypertension rates documented among native Siberians in the post-Soviet period. These findings underscore the importance of considering the influence of biological adaptation to regional environmental conditions in structuring health changes associated with economic development and lifestyle change.

Anthropometric correlates of C-reactive protein among indigenous Siberians.

C-reactive protein (CRP) is an inflammatory marker, which at low-level elevations is associated with increased cardiovascular risk. Although CRP has been extensively investigated in North American and European settings, few studies have measured CRP among non-Western groups. The present study used dried whole blood spot samples to examine high-sensitivity CRP concentrations among the Yakut (Sakha) of Siberia (85 females, 56 males; 18-58 years old). Our goals were: (1) to compare Yakut CRP concentrations with other populations; (2) to investigate sex differences; and (3) to explore anthropometric correlates of CRP. Results indicate that serum equivalent CRP concentrations are similar to those from industrializing nations, lower than US and European values, and greater than Japanese concentrations. Yakut men and women display similar CRP concentrations; however, CRP was significantly higher among men after adjustment for body fat, age, and smoking. Positive associations were documented between CRP and BMI, body fat, and central adiposity.

Adaptive dimensions of health research among indigenous Siberians.

Present evidence suggests that modern humans were the first hominid species to successfully colonize high-latitude environments (> or =55 degrees N). Given evidence for a recent (<200,000 years) lower latitude naissance of modern humans, the global dispersal and successful settlement of arctic and subarctic regions represent an unprecedented adaptive shift. This adaptive shift, which included cultural, behavioral, and biological dimensions, allowed human populations to cope with the myriad environmental stressors encountered in circumpolar regions. Although unique morphological and physiological adaptations among contemporary northern residents have been recognized for decades, human biologists are only now beginning to consider whether biological adaptations to regional environmental conditions influence health changes associated with economic modernization and lifestyle change. Recent studies have documented basal metabolic rates (BMRs) among indigenous Siberian populations that are systematically elevated compared to lower latitude groups; this metabolic elevation apparently is a physiological adaptation to cold stress experienced in the circumpolar environment. Important health implications of metabolic adaptation are suggested by research with the Yakut (Sakha), Evenki, and Buriat of Siberia. BMR is significantly positively correlated with blood pressure, independently of body size, body composition, and various potentially confounding variables (e.g., age and smoking). Further, this research has documented a significant negative association between BMR and LDL cholesterol, which remains after controlling for potential confounders; this suggests that high metabolic turnover among indigenous Siberians has a protective effect with regard to plasma lipid levels. These results underscore the importance of incorporating an evolutionary approach into health research among northern populations.

The emergence of obesity among indigenous Siberians.

Once considered a disease of affluence and confined to industrialized nations, obesity is currently emerging as a major health concern in nearly every country in the world. Available data suggest that the prevalence rate of obesity has reached unprecedented levels in most developing countries, and is increasing at a rate that far outpaces that of developed nations. This increase in obesity has also been documented among North American circumpolar populations and is associated with lifestyle changes related to economic development. While obesity has not been well studied among indigenous Siberians, recent anthropological studies indicate that obesity and its associated comorbidities are important health problems.The present study examines recent adult body composition data from four indigenous Siberian populations (Evenki, Ket, Buriat, and Yakut) with two main objectives: 1) to determine the prevalence of overweight and obesity among these groups, and 2) to assess the influence of lifestyle and socioeconomic factors on the development of excess body fat. The results of this study indicate that obesity has emerged as an important health issue among indigenous Siberians, and especially for women, whose obesity rates are considerably higher than those of men (12% vs. 7%). The present study investigated the association between lifestyle and body composition among the Yakut, and documented substantial sex differences in lifestyle correlates of obesity. Yakut men with higher incomes and who owned more luxury consumer goods were more likely to have excess body fat while, among Yakut women, affluence was not strongly associated with overweight and obesity.

Validation of the Functional Assessment of Chronic Illness Therapy Fatigue Scale relative to other instrumentation in patients with rheumatoid arthritis.

OBJECTIVE: This study validated a brief measure of fatigue in rheumatoid arthritis (RA), the Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue Scale. METHODS: The FACIT Fatigue was tested along with measures previously validated in RA: the Multidimensional Assessment of Fatigue (MAF) and Medical Outcomes Study Short-Form 36 (SF-36) Vitality. The sample included 636 patients with RA enrolled in a 24 week double blind, randomized clinical trial (RCT) of adalimumab versus placebo. RESULTS: The FACIT Fatigue showed good internal consistency (alpha = 0.86 to 0.87), strong association with SF-36 Vitality (r = 0.73 to 0.84) and MAF (r = -0.84 to -0.88), and the ability to differentiate patients according to clinical change using the American College of Rheumatology (ACR) response criteria (ACR 20/50/70). Psychometric performance of the FACIT Fatigue scale was comparable to that of the other 2 fatigue measures. A minimally important difference in FACIT Fatigue change score of 3-4 points was confirmed in a separate sample of 271 patients with RA enrolled in a second double blind RCT of adalimumab versus placebo. CONCLUSION: The FACIT Fatigue is a brief, valid measure for monitoring this important symptom and its effects on patients with RA.

Using multiple anchor- and distribution-based estimates to evaluate clinically meaningful change on the Functional Assessment of Cancer Therapy-Biologic Response Modifiers (FACT-BRM) instrument.

OBJECTIVE: The interpretation of health-related quality of life (HRQL) data from clinical trials can be enhanced by understanding the degree of change in HRQL scores that is considered meaningful. Our objectives were to combine distribution-based and two anchor-based approaches to identify minimally important differences (MIDs) for the 27-item Trial Outcome Index (TOI), the seven-item Social Well-Being (SWB) subscale, and the six-item Emotional Well-being (EWB) subscale from the Functional Assessment of Cancer Therapy-Biological Response Modifiers (FACT-BRM) instrument. METHODS: Distribution-based MIDs were based on the standard error of measurement. Anchor-based approaches utilized patient-reported global rating of change (GRC) and change in physician-reported performance status rating (PSR). Correlations and weighted kappa statistics were used to assess association and agreement between the two anchors. FACT-BRM changes were evaluated for three time periods: baseline to month 1, month 2 to month 3, and month 5 to month 6. RESULTS: Association between GRC and change in PSR was poor. Correlation between the anchors and HRQL change scores was largest at month 1 and decreased through month 6. Combining results from all approaches, the MIDs identified were 5-8 points for the TOI, 2 points for the SWB subscale, and 2-3 points for the EWB subscale. CONCLUSIONS: We combined patient-reported estimates, physician-reported estimates, and distribution-based estimates to derive MIDs for HRQL outcomes from the FACT-BRM. These results will enable interpretation of treatment group effects in a clinical trial setting, and they can be used to estimate sample size or power when designing future studies.

Urinary incontinence among mothers of multiples: the protective effect of cesarean delivery.

OBJECTIVE: The purpose of this study was to assess the impact of delivery mode on the risk of urinary incontinence among women with previous multiple childbirth. STUDY DESIGN: A 77-item questionnaire was administered to 733 mothers of multiples. Multivariate regression was used to control for potentially confounding variables. RESULTS: The mean rate of stress urinary incontinence among women who were delivered by cesarean-only delivery was 39.6%, which was significantly lower than the 60.4% among women who reported previous vaginal births (P =.005). Cesarean-only delivery was associated with a markedly reduced risk (odds ratio, 0.52; P =.002) after controlling for age, parity, and body mass index by multivariate regression. Weaker associations were found for age (odds ratio, 1.08), body mass index (odds ratio, 1.06), and parity (odds ratio, 1.46). Urge incontinence was associated with parity, body mass index, and age, but not delivery mode (P =.76). CONCLUSION: Vaginal delivery represents a major risk factor for stress incontinence among mothers of multiples. Delivery by cesarean delivery only confers an independent protective effect.

Quality of life in patients with newly diagnosed chronic phase chronic myeloid leukemia on imatinib versus interferon alfa plus low-dose cytarabine: results from the IRIS Study.

PURPOSE: Quality of life (QOL) outcomes in patients with chronic myeloid leukemia (CML) were evaluated in an international phase III study. PATIENTS AND METHODS: Newly diagnosed patients with chronic phase CML were randomly assigned to imatinib or interferon alfa plus subcutaneous low-dose cytarabine (IFN+LDAC). Cross-over to the other treatment was permitted because of intolerance or lack of efficacy. Patients completed cancer-specific QOL (Functional Assessment of Cancer Therapy-Biologic Response Modifiers) and utility (Euro QoL-5D) questionnaires at baseline and during treatment (n = 1,049). The primary QOL end point was the Trial Outcome Index (TOI; a measure of physical function and well-being). Secondary end points included social and family well-being (SFWB), emotional well-being (EWB), and the utility score. Primary analyses were intention to treat with secondary analyses accounting for cross-over. RESULTS: Patients receiving IFN+LDAC experienced a large decline in the TOI, whereas those receiving imatinib maintained their baseline level. Treatment differences at each visit were significant (P <.001) and clinically relevant in favor of imatinib. Mean SFWB, EWB, and utility scores were also significantly better for those patients taking imatinib. Patients who crossed over to imatinib experienced a large increase in TOI; significant (P <.001) differences were observed between patients who did and did not cross over in favor of imatinib. CONCLUSION: Imatinib offers clear QOL advantages compared with IFN+LDAC as first-line treatment of chronic phase CML. In addition, patients who cross over to imatinib from IFN+LDAC experience a significant improvement in QOL compared with patients who continue to take IFN+LDAC.

Prevalence of anal incontinence among mothers of multiples and analysis of risk factors.

OBJECTIVE: The object of this study was to determine the prevalence of anal incontinence among women with previous multiple pregnancy and childbirth and assess risk factors. STUDY DESIGN: A 77-item questionnaire was administered to 769 mothers of multiples. Statistical analyses included chi(2), Student t test, and logistic regression. RESULTS: Seven hundred thirty-three (95.3%) women completed the survey, 94% of them white, with a median age of 37 years. Fecal incontinence affected 10% (6.3% arose during pregnancy, 40.6% after delivery, 53.1% unrelated to childbirth). Although delivery by cesarean section only was associated with lower prevalence in univariate analysis (5.8% vs 11%, P=.02), age was the only significant covariate in multivariate regression (P=.0001). Flatal incontinence affected 25.2% (21.2% during pregnancy, 30.3% after delivery, 48.5% unrelated), increasing with age (P=.0001). Soiling affected 10%, increasing with age (P=.0001). CONCLUSION: Mothers of multiples reported substantial rates of fecal (10%) and flatal (25.2%) incontinence. Advancing age was the major risk factor. Delivery by cesarean section only was not significantly protective, although elective (before labor) cesarean deliveries were not separately assessed.

Climatic influences on basal metabolic rates among circumpolar populations.

This article examines evidence for elevations in basal metabolic rate (BMR) among indigenous Northern (circumpolar) populations and considers potential mechanisms and the adaptive basis for such elevations. Data on BMR among indigenous (n = 109 males; 122 females) and nonindigenous (n = 15 males; 22 females) circumpolar groups of North America and Siberia are compiled and compared to predicted BMRs based on three different references: body surface area (Consolazio et al., 1963), body mass (Schofield, 1985), and fat-free mass (Poehlman and Toth, 1995). Regardless of which reference is used, indigenous circumpolar groups show systematic and statistically significant elevations in BMR ranging from +7% to +19% above predicted values for indigenous men and from +3 to +17% for indigenous women. Nonindigenous males also show elevations in BMR, although not to the same extent as in indigenous men (deviations = +3 to +14%), whereas nonindigenous females show no clear evidence of elevated BMRs (deviations = -7 to +5%). This pattern of variation between indigenous and nonindigenous groups suggests that both functional and genetic factors play a role in metabolic adaptation to northern climes. Recent studies on the ecology and genetics of thyroid function offer insights into the mechanisms through which indigenous circumpolar populations may regulate metabolic rates. Studies of seasonal variation in thyroid hormone levels suggest that indigenous circumpolar populations may have a greater capacity to elevate BMR during severe cold than nonindigenous groups. Recent twin studies indicate a significant genetic component of thyroid responses to environmental stressors. Further research exploring the genetics of seasonal variation in thyroid function and BMR among circumpolar groups would advance understanding of the role that selection may have played in shaping metabolic variation.