The Alaska Education and Research Towards Health (EARTH) Study: cancer risk factors

Ten-year weight gain is not associated with multiple cardiometabolic measures in Alaska EARTH study participants

BACKGROUND AND AIMS

Alaska Native (AN) traditional lifestyle may be protective against chronic disease risk. Weight gain in adulthood has been linked to increases in chronic disease risk among other populations; yet, its impact among Alaska Native people has never been evaluated. We aimed to evaluate changes in obesity-related metrics over time, and determine associations of changes with cardiometabolic markers of chronic disease risk among AN people.

METHODS AND RESULTS

Study participants enrolled in the southcentral Alaska Education and Research Towards Health Study in 2004-2006 were invited to participate in a follow-up study conducted 2015-2017. Of the original 1320 participants, 388 completed follow-up health assessments consisting of multiple health surveys, anthropometric measurements, and cardiometabolic measures including blood sugars, blood lipids, and blood pressure. Differences in measurements between visits were determined and associations of weight change with cardiometabolic measures evaluated. Body mass index increased by 3.7 kg/m2 among men and 4.8 kg/m2 among women. Hip circumference (1.1 cm, p < 0.01) and waist circumference (0.7 cm, p < 0.01) increased among women; only waist circumference increased among men (1.6 cm, p < 0.01). Among men, there were no associations of weight change with cardiometabolic measures. Among women, there was an inverse association between weight gain and high-density lipoprotein cholesterol only (0.17 mg/dL (CI: -3.1, -0.03), p = 0.02).

CONCLUSIONS

While weight increase over a 10-year period was not associated with substantive changes in cardiometabolic measures among AN men, there was a decrease in high density lipid cholesterol associated with weight gain among AN women.

Incorporating Participant and Clinical Feedback into a Community-Based Participatory Research Study of Colorectal Cancer Among Alaska Native People

Alaska Native (AN) people have among the highest rates of colorectal cancer (CRC) globally. We are developing a community-based participatory research (CBPR) informed program to understand risk and protective factors contributing to these high rates. In 2018, we conducted a pilot study to test feasibility of recruiting participants from the Alaska Native Medical Center CRC Screening Clinic into a prospective epidemiologic study. Post-pilot study completion, we conducted focus groups (n = 2) with participants and key informant interviews (n = 7) with research and clinical staff to understand study experiences. During 106 days of recruitment, 30 participants enrolled in the pilot study. Over half (60%) were female, and most (67%) were aged 40-59 years. Key themes that emerged from the participant focus groups were: the desire to contribute to improving the health of AN people as a key driver of participation; an overall positive experience with the study; the benefit of clinical staff notifying patients about the study; the need to clearly explain the purpose of each biospecimen collected; barriers to participation; and, the importance of returning study results to the community. Key themes from research and clinical staff interviews included: the study not interfering with clinical duties; the importance of relationships between clinical and research staff; the importance of research staff flexibility; and, comments on specific study procedures. As part of the CBPR process, this feedback will be incorporated into study protocols. We are building this pilot work into a larger prospective study that will inform primary prevention programs.

Agreement between self-reported and central cancer registry-recorded prevalence of cancer in the Alaska EARTH study

Reliance on self-reported health status information as a measure of population health can be challenging due to errors associated with participant recall. We sought to determine agreement between self-reported and registry-recorded site-specific cancer diagnoses in a cohort of Alaska Native people. We linked cancer history information from the Alaska Education and Research Towards Health (EARTH) cohort and the Alaska Native Tumor Registry (ANTR), and calculated validity measures (sensitivity, specificity, positive predictive value, negative predictive value, kappa). Multiple logistic regression models were used to assess independent associations of demographic variables with incorrect reporting. We found that among Alaska EARTH participants, 140 self-reported a history of cancer, and 99 matched the ANTR. Sensitivity ranged from 79% (colorectal cancer) to 100% (prostate cancer); specificity was over 98% for all-sites examined. Kappa was higher among prostate and female breast cancers (κ=0.86) than colorectal cancers (κ=0.63). Women (odds ratio [OR] (95% confidence interval [CI]): 2.8 (1.49-5.31)) and participants who were older than 50 years (OR (95% CI): 2.8 (1.53-4.12)) were more likely to report incorrectly. These data showed good agreement between self-reported and registry-recorded cancer history. This may be attributed to the high quality of care within the Alaska Tribal Health System, which strongly values patient-provider relationships and the provision of culturally appropriate care.

Follow-up Study Methods for a Longitudinal Cohort of Alaska Native and American Indian People Living within Urban South Central Alaska: The EARTH Study

Longitudinal data are needed to investigate chronic disease causation and improve prevention efforts for Alaska Native and American Indian (ANAI) people. This paper describes the methods used to conduct follow-up data collection of a longitudinal cohort that enrolled ANAI adults between 2004 and 2006 in south central Alaska. The follow-up study re-examined ANAI participants in a large, urban centre in south central Alaska between 2015 and 2017. Computerized surveys were used to collect self-reported health, lifestyle, physical activity, and diet data. Clinical measurements included blood pressure, fasting blood glucose and lipid panel, urine albumin/creatinine, height, weight, and waist and hip circumference. Participants were provided individual results at the conclusion of their visit. A total of 1320 south central Alaska study participants completed the baseline visit. Study staff attempted to contact all living cohort members for inclusion in the follow-up study. More than 11,000 attempted contacts were made. Of the 637 available for participation, 388 completed the follow-up visit. The proportion of women increased from baseline to follow-up examinations (67 vs. 72%, p < 0.01). Self-reported health status of being married or living as married (46% vs. 39%, p < 0.01), and those reporting being employed or self-employed (55% vs. 47%, p < 0.01) were higher at follow-up when compared to baseline. Almost all participants at follow-up (97%) agreed to long-term storage of biological specimens for future study. Despite demographic differences between the follow-up and baseline cohorts, longitudinal data collected will provide novel insight on chronic disease development and prevention for ANAI people as well as other populations.

Cancer incidence and associations with known risk and protective factors: the Alaska EARTH study

PURPOSE

Cancer is the leading cause of mortality among Alaska Native (AN) people. The Alaska Education and Research Towards Health (EARTH) cohort was established to examine risk and protective factors for chronic diseases, including cancer, among AN people. Here, we describe the cancer experience of the Alaska EARTH cohort in relation to statewide- and region-specific tumor registry data, and assess associations with key cancer risk factors.

METHODS

AN participants were recruited into the Alaska EARTH cohort during 2004-2006. Data collected included patient demographic, anthropometric, medical and family history, and lifestyle information. This study linked the Alaska EARTH data with cancer diagnoses recorded by the Alaska Native Tumor Registry (ANTR) through 12/31/15. We compared EARTH incidence to ANTR statewide incidence. We examined independent associations of smoking status, diet, BMI, and physical activity with incident all-site cancers using multivariable-adjusted Cox proportional hazards models.

RESULTS

Between study enrollment and 2015, 171 of 3,712 (4.7%) Alaska EARTH study participants were diagnosed with cancer. The leading cancers among Alaska EARTH participants were female breast, lung, and colorectal cancer, which reflected those observed among AN people statewide. Incidence (95% CI) of cancer (all sites) among Alaska EARTH participants was 629.7 (510.9-748.6) per 100,000 person-years; this was comparable to statewide rates [680.5 (660.0-701.5) per 100,000 population]. We observed lower risk of all-sites cancer incidence among never smokers.

CONCLUSIONS

Cancer incidence in the Alaska EARTH cohort was similar to incidence observed statewide. Risk and protective factors for leading cancers among AN people mirror those observed among other populations.

Who is research serving? A systematic realist review of circumpolar environment-related Indigenous health literature

BACKGROUND

Addressing factors leading to health disparities in the Circumpolar North require approaches that consider and address the social determinants of health including on-going colonization. Today, colonization and related policies and processes, continue to manifest in the marginalization of Indigenous knowledge, particularly its use in research; however, Indigenous populations have moved from being research subjects to leaders and consumers of environmental health research. Given the tensions that exist between how health research is conducted, how the results are mobilized, and who has control and access to the results, we examine how peer-reviewed environment-related Indigenous health research in the Circumpolar North is serving the needs of Indigenous communities, governments, and organizations.

METHODS

A modified systematic-realist literature review was conducted. Three databases were searched for peer-reviewed literature published from 2000 to 2015. Articles were included if the research focused on the intersection of the environment and health in Northern Canada and/or Alaska. A total of 960 unique records were screened for relevance, and 210 articles were analysed.

RESULTS

Of these relevant articles, 19% discussed how Indigenous peoples were engaged in the research. There was a significant increase in reporting participatory, community-based methods over time; the proportion of articles reporting community-engagement varied by research topic; quantitative research articles were significantly less likely to report community-engaged methods; and most articles did not clearly report how the results were shared with the community.

CONCLUSION

The results raise a number of questions for the field of Circumpolar environment-related Indigenous health research, including whether or how authors of peer-reviewed literature should (or should not) be obliged to describe how research is serving Northern Indigenous communities. The results are intended to stimulate further conversations and bridge perceived dichotomies of quantitative/qualitative, Western/Indigenous, and empirical/community driven research approaches, as well as underlying assumptions that frame health research.

Research on indigenous elders: from positivistic to decolonizing methodologies

Although indigenous peoples have lower life expectancies than the social majority populations in their countries, increasing numbers of indigenous people are living into old age. Research on indigenous elders is informed by a number of research traditions. Researchers have mined existing data sets to compare characteristics of indigenous populations with non-indigenous groups, and these findings have revealed significant disparities experienced by indigenous elders. Some investigators have attempted to validate standardized research tools for use in indigenous populations. Findings from these studies have furthered our knowledge about indigenous elders and have highlighted the ways in which tools may need to be adapted to better fit indigenous views of the constructs being measured. Qualitative approaches are popular, as they allow indigenous elders to tell their stories and challenge non-indigenous investigators to acknowledge values and worldviews different from their own. Recently, efforts have extended to participatory and decolonizing research methods, which aim to empower indigenous elders as researchers. Research approaches are discussed in light of the negative experiences many indigenous peoples have had with Eurocentric research. Acknowledgment of historical trauma, life-course perspectives, phenomenology, and critical gerontology should frame future research with, rather than on, indigenous elders.