Cancer Screening Prevalence among Participants in the Southcentral Alaska Education and Research towards Health (EARTH) Study at Baseline and Follow-Up

Alaska Native communities are working to prevent cancer through increased cancer screening and early detection. We examined the prevalence of self-reported colorectal (CRC), cervical, and breast cancer screening among Alaska Native participants in the southcentral Alaska Education and Research toward Health (EARTH) study at baseline (2004-2006) and ten-year follow-up (2015-2017); participant characteristics associated with screening; and changes in screening prevalence over time. A total of 385 participants completed questionnaires at follow-up; 72% were women. Of those eligible for CRC screening, 53% of follow-up participants reported a CRC screening test within the past 5 years, significantly less than at baseline (70%) (p = 0.02). There was also a significant decline in cervical cancer screening between baseline and follow-up: 73% of women at follow-up vs. 90% at baseline reported screening within the past three years (p < 0.01). There was no significant difference in reported breast cancer screening between baseline (78%) and follow-up (77%). Colorectal and cervical cancer screening prevalence in an urban, southcentral Alaska Native cohort declined over 10 years of follow-up. Increased cancer screening and prevention are needed to decrease Alaska Native cancer-related morbidity and mortality.

Perchlorate exposure does not modulate temporal variation of whole-body thyroid and androgen hormone content in threespine stickleback

Previously we showed that exposure of threespine stickleback (Gasterosteus aculeatus) to the endocrine disruptor perchlorate results in pronounced structural changes in thyroid and gonad, while surprisingly, whole-body thyroid hormone concentrations remain unaffected. To test for hormone titer variations on a finer scale, we evaluated the interactive effects of time (diel and reproductive season) and perchlorate exposure on whole-body contents of triiodothyronine (T3), thyroxine (T4), and 11-ketotestosterone (11-KT) in captive stickleback. Adult stickleback were exposed to 100ppm perchlorate or control water and sampled at 4-h intervals across the 24-hday and at one time-point (1100h) weekly across the reproductive season (May-July). Neither whole-body T3 nor T4 concentration significantly differed across the day in control or perchlorate treated stickleback. Across the reproductive season, whole-body T3 concentration remained stable while T4 significantly increased. However, neither hormone concentration was significantly affected by perchlorate, verifying our previous studies. The concentration of whole-body 11-KT, a major fish androgen, displayed significant diel variation and also steadily declined across the reproductive season in untreated males; perchlorate exposure did not influence the concentration of 11-KT in either diel or reproductive season schedules. Diel and reproductive season variations in 11-KT content in male stickleback are likely related to reproductive physiology and behavior. The observed increase in T4 content across the reproductive season may be reflective of increased energy investment in reproduction near the end of the life cycle.