Safety behaviours among Alaskan Native and American Indian people living in Alaska.

OBJECTIVE: To examine self-reported safety behaviours among 3828 Alaskan Native and American Indian people enrolled in the Alaska Education and Research Towards Health (EARTH) Study, 2004-2006. DESIGN: A cross-sectional analysis of baseline data from a cohort study. A non-random sample of participants (2322 women and 1506 men) aged > or =18 years from three regions of Alaska completed questions on safety behaviours as part of a comprehensive health and lifestyle computer-assisted self-administered questionnaire. RESULTS: Most participants reported never driving after drinking (94.1%) or riding with a driver who had been drinking (91.3%). Fewer (74.1%) participants reported using a seatbelt always or almost always when riding in a vehicle. Only about half (55%) always kept to the speed limit when driving or used a personal flotation device when boating (51.5%). Even fewer (20.5%) reported using a helmet when riding on off-road vehicles, including four-wheelers and snowmobiles. Factors identified among those least likely to use safety devices and practise good safety behaviours are: younger age, lower household income and education, non-married, speaking only English at home, and a self-reported health status of poor to fair (p<0.05). CONCLUSIONS: Recommendations for future injury prevention efforts in this population are to increase use of personal flotation devices while boating and address the underuse of helmets with off-road vehicles. Limited prevention resources should be used to target those who engage in risky behaviours to maximise programme impact.

Leukemia, lymphoma, and multiple myeloma in Alaskan natives.

All Alaskan Native patients diagnosed with leukemia, lymphoma, multiple myeloma, and related cancers during the time period 1969-83 were identified. Of 72 biopsy-confirmed cases, lymphoma was diagnosed in 37 (including mycosis fungoides in 5), leukemia in 22, multiple myeloma in 11, and other lymphoreticular cancers in 2. Compared to the rates for U.S. whites, incidence rates were low for leukemia and lymphoma (especially Hodgkin's disease), but not for multiple myeloma in males. There was an apparent increase over time in lymphomas in males, while no increase occurred in females, nor for leukemia or multiple myeloma in either sex.

Attachment of antinuclear antibodies to nasopharyngeal carcinoma or other cells during preparation of biopsy imprints.

The presence of Epstein-Barr virus (EBV) genomes in nasopharyngeal and other carcinomas or Burkitt's and other B-cell lymphomas can be established by the demonstration of viral nucleic acid sequences in DNA extracts from biopsy specimens, the detection of EBV-associated nuclear antigen (EBNA) in biopsy imprints, and the inhibition of leukocyte migration by tumor extracts. Of these techniques, the detection of EBNA-positive tumor cells can be performed most readily in the laboratory. This report shows that a patient's antibodies to nuclear antigens can gain access to cell nuclei during the preparation of imprints. If the antibodies are directed against EBNA, nuclear immunofluorescence is elicited solely in the tumor cells when only complement (C') and fluorescein-labeled antibodies to C' are applied to the imprints without prior exposure to anti-EBNA-positive sera. If nonspecific antinuclear antibodies (ANA) are involved, the nuclear immunofluorescence seen in the EBNA-specific and control assays is not limited to the tumor cells but extends to any normal cells that may be present in the imprints. Furthermore, nuclear fluorescence is elicited when solely an anti-human IgG conjugate is applied because ANA is measurable by indirect immunofluorescence, whereas detection of EBNA requires augmentation of the antigen-antibody complexes by C', which differentiates further between EBNA-specific and nonspecific staining. Attachment of antibodies to nuclei can be avoided by minimizing the deposit of blood during imprint preparation and by rapid drying of the imprints. Similar results are obtained experimentally when smears of lymphoblasts are made in the presence of anti-EBNA or ANA.

Nasopharyngeal carcinoma in an Alaskan Eskimo family: report of three cases.

Nasopharyngeal carcinoma (NPC) has been reported to occur in Alsaka Natives (Eskimos, Indians, and Aleuts) at a rate greater than 15 times the rate for U.S. whites. At least 3 cases of NPC have occurred in close relatives of a Northern Alaskan Eskimo family. All 3 patients had poorly differentiated tumors and have died. Blood groups, HLA antigens, and antibodies to Epstein-Barr virus (EBV) were studied in the family members. EBV titers were elevated in the 1 NPC patient tested and in 1 of 15 other family members tested. All family members studied except 1 were of blood group A, Rh-positive, and HLA types AW24, CW3, CW40/A2, CW2 and B27. This was the first report of more than 2 cases of NPC in a single family in the United States.

Cancer in Alaskan Indians, Eskimos, and Aleuts.

Standard incidence ratios for cancers that occurred during 1969--73 among Alaskan Natives (Indians and Eskimo-Aleuts) were reported. Although data suggested that the overall rate of cancer in this population was close to that of U.S. whites, differences existed for certain cancer sites. Thus increased risks in Alaskan Natives were observed for nasopharyngeal, salivary gland, kidney, and gallbladder and liver cancers. Conversely, decreased risks were found for cancers of the lung, larynx, bladder, prostate gland, breast, and corpus uterus and for melanoma and lymphoma.

Cancers of the gallbladder and biliary tract in Alaskan natives: 1970--79.

The records of Alaskan Native patients with gallbladder and extrahepatic bile duct cancers diagnosed during 1970--79 were reviewed. Of 34 cases identified, the primary cancer was in the gallbladder in 29, resulting in age-adjusted incidence rates for gallbladder cancer of 4.4 for males and 17.6 for females. On the basis of calculations applying cancer incidence rates for U.S. whites to the Alaska Native population, a greater than expected number of both Eskimo and Indian patients were diagnosed. A 5-year review of cholecystectomies indicated that nonmalignant gallbladder disease was also elevated in both Indians and Eskimos.

Hepatitis B-related sequelae. Prospective study in 1400 hepatitis B surface antigen-positive Alaska native carriers.

A total 1400 hepatitis B surface antigen-positive Alaska natives, 824 men and 576 women of all ages, were followed up prospectively over a period of 7815 carrier years for the development of sequelae related to chronic hepatitis B virus infection. During the observation period, 20 cases of hepatocellular carcinoma, 14 cases of chronic active hepatitis, 8 cases of cirrhosis, and 1 case of glomerulonephritis developed in this cohort. The annual incidence of hepatocellular carcinoma was 387 per 100,000 for men and 63 per 100,000 for women. The incidence of chronic active hepatitis and cirrhosis was 193 and 107 per 100,000 in men and 158 and 95 per 100,000 in women, respectively. No cases of either essential mixed cryoglobulinemia or necrotizing vasculitis were seen. Sixty of the hepatitis B surface antigen-positive carriers died, with 13 (21.7%) of the deaths due to hepatocellular carcinoma. The leading cause of death in this group was malignant neoplasms compared with accidents in the general Alaska native population.

Immunogenicity of pneumococcal revaccination in patients with chronic disease.

BACKGROUND: To prevent serious pneumococcal infections, 23-valent pneumococcal polysaccharide vaccine is recommended for individuals over 24 months of age with chronic predisposing diseases and for healthy older adults. This nonrandomized controlled study in rural Alaska assessed the immunogenicity of revaccination in adults. METHODS: Twenty-six adults, 33 to 88 years of age, vaccinated a mean of 7.4 years before this study, were matched to 26 previously unvaccinated subjects by age, number of chronic diseases, sex, and ethnicity. One or more chronic diseases were validated in 62% of subjects (32 of 52). All received a first or second intramuscular dose of pneumococcal vaccine. Antibody levels were determined by radioimmunoassay for 12 pneumococcal capsular serotypes immediately before and 20 to 84 days after vaccination. RESULTS: Six to 9 years after primary vaccination, over one third of serotype-specific antibody levels were below 500 ng of antibody nitrogen per milliliter, equal to the percentage in unvaccinated subjects of similar age. Antibody levels against all pneumococcal serotypes rose to similar levels after primary vaccination and revaccination, and 54% and 55%, respectively, of subjects who received primary vaccination and revaccination had at least a 1.4-fold increase in antibody levels. Only the antibody level for serotype 4 remained low. Neither gender nor age affected peak response. For those with chronic diseases, there was a trend toward fewer low antibody levels against three or more serotypes after revaccination (two subjects [13%]) than after primary vaccination (five subjects [31%]). CONCLUSIONS: Following the initial immunization of high-risk and elderly patients with pneumococcal polysaccharide, pneumococcal antibody levels appear to wane with time. Primary vaccination and revaccination 6 or more years after a first dose of pneumococcal vaccine stimulate comparable mean antibody levels.

Prevalence of diabetes mellitus in Alaskan Eskimos, Indians, and Aleuts.

The prevalence of diabetes mellitus in Alaska Natives has been thought to be low, but no survey of this condition in all natives has been conducted. Medical records from 1979 to 1985 were reviewed to determine the prevalence of diagnosed diabetes mellitus in Alaska Natives. Computerized outpatient and inpatient medical record data and clinician reports were used to identify cases. As of December 1985, 610 living Alaska Natives fulfilled diagnostic criteria for diabetes. Type II diabetes mellitus was found in 564 subjects, type I diabetes was found in 15 subjects, and unspecified type of diabetes was found in 31 subjects. The overall age-adjusted prevalence of diabetes mellitus, 15.7/1000, was lower than the overall United States rate of 24.7/1000. However, age-adjusted prevalence varied considerably by ethnic group; the prevalence was 27.2/1000 among Aleuts, 22.0/1000 among Alaskan Indians, and 8.8/1000 among Alaskan Eskimos. Rates within the Eskimo subgroups varied by a factor of four. Compared with previous reports, the prevalence of diabetes mellitus in Alaskan Eskimos appears to have increased. Diabetes mellitus is no longer a rare condition among Alaska Natives.

Diabetes prevalence, incidence, and complications among Alaska Natives, 1987.

OBJECTIVE: To provide descriptive epidemiological data on diabetes mellitus among Alaska Natives, including incidence, updated prevalence, and incidence rates of ESRD, LEA, MI, and stroke in the diabetic population. RESEARCH DESIGN AND METHODS: In IHS and tribal contract hospitals and clinics throughout Alaska, Alaskan Indians, Eskimos, and Aleuts living in Alaska with documented diabetes mellitus were studied from 1986 to 1987. RESULTS: The number of diabetic patients increased from 610 to 708, and the prevalence changed from 15.7 to 17.4/1000 (not a statistically significant increase). Incidence rates per 10,000 diabetic person-yr for complications were 38 for ESRD, 69 for LEA, 92 for MI, and 92 for stroke. CONCLUSIONS: The prevalence of diabetes mellitus increased during the period of observation, but not to a statistically significant degree. Incidence rates for diabetes are lower than for the U.S. general population, but complications rates are as high as those in other diabetic populations.

Prevalence of diabetes mellitus in pregnancy among Yup'ik Eskimos, 1987-1988.

OBJECTIVE: To evaluate the prevalence of diabetes mellitus in pregnancy in Yup'ik Eskimos. RESEARCH DESIGN AND METHODS: A retrospective review of consecutive birth-log data and medical records was conducted. Records were taken from the primary care and tertiary referral facilities in Alaska Area Native Health Service. Some 630 consecutive deliveries were reviewed from 1 March 1987 to 29 February 1988, with 25 excluded for ancestry other than Alaska Native. Another 605 Alaska Native patient charts were reviewed, with 545 Alaska Native patients screened for diabetes in pregnancy. The study population had a mean age of 25.6 yr, mean gravidity of 3.4, mean parity of 1.9, and mean birth weight of 3567 +/- 493 g. RESULTS: Patients were screened with a 50-g glucose oral load with a plasma glucose 1 h later. 156 of 605 (25.7%) patients, with a screen > or = 7.8 mM received a 100-g OGTT. Of 605, 35 (5.8%) patients met O'Sullivan criteria, and 2 of 605 (0.3%) patients met WHO criteria for previous diabetes mellitus, for a total 37 of 605 (6.7% [corrected]) women with diabetes in pregnancy. The subjects who met O'Sullivan criteria had statistically greater mean age (29.9 yr), gravidity (4.9), parity (2.9), and birth weight of their infants (3678 +/- 389 g), compared with women with a screen < 7.8 mM. CONCLUSIONS: The prevalence of diabetes in pregnancy among Yup'ik Eskimos is twice the rate for the U.S. for all races, despite the Yup'ik having the lowest rate of diabetes mellitus among Alaska Natives. This may represent a large number of undiagnosed patients with impaired glucose tolerance, and may reflect the wide-spread dietary and life-style changes that have occurred in the Yup'ik in the last 30 yr. The Yup'ik present a unique opportunity to apply prevention techniques in a population with an emerging problem with glucose tolerance.

Diabetes mellitus in Alaskan Yup'ik Eskimos and Athabascan Indians after 25 yr.

OBJECTIVE: To estimate the prevalence of diabetes mellitus and overweight in two populations of Alaska Natives and to compare the results with previous data. RESEARCH DESIGN AND METHODS: Participants' heights, weights, and random plasma glucose levels were determined. Those with a glucose of greater than or equal to 6.72 mM received a follow-up glucose-tolerance test, interpreted by WHO criteria. Overweight was defined by National Center for Health Statistics criteria and also by criteria used in previous studies. The subjects were Eskimo and Athabascan residents greater than or equal to 40 yr of age in 15 villages in southwestern Alaska. RESULTS: Diabetes prevalence was 4.7% for Eskimos and 10.0% for Indians. Among Eskimo men and women, the prevalence of overweight was 34 and 56%, respectively, among Indian men and women, it was 29 and 55%, respectively. Comparisons with past data indicate that the prevalence of diabetes has increased from 1.7% in 1962 for Eskimos and 1.8% in 1969 for Indians. CONCLUSIONS: The prevalence of diabetes appears to have increased among Eskimos and Indians in Alaska. Overweight appears to be a significant problem in both groups.

The diet of Alaska Native adults: 1987-1988.

Although in the past, rates of heart disease, cancer, and diabetes were lower in Alaska Natives than in US whites, these diseases are now increasing. The rate of iron-deficiency anemia for Alaska Natives continues to be higher than that in the general population. To understand the role of diet in these chronic diseases, seasonal dietary intakes of 351 Alaska Native adults from 11 communities were assessed during 1987-1988. Alaska Natives consumed more energy (19%), protein (39%), fat (21%), carbohydrate (13%), iron (25%), vitamin A (53%), and vitamin C (31%), but less calcium (19%) than did the general US adult population [National Health and Nutrition Examination Survey II (NHANES II)]; Alaska Natives consumed six times more fish but less fruits and vegetables. Results suggest that energy and protein intakes decreased in the last 30 y but the proportion of energy from fat (37%) remained unchanged. High fish consumption and large seasonal dietary variations persisted, which may protect against chronic diseases. However, excess energy and fat and low calcium, fruit, and vegetable intakes may be contributing to recent increases in chronic diseases. Dietary guidelines are proposed.

p53 is not mutated in hepatocellular carcinomas from Alaska Natives.

Hepatocellular carcinoma is common among Alaska Natives. The known risk factor in this population is hepatitis B viral infection; fungal toxins, including aflatoxin B1, have not been detected in foodstuffs. In this series of 14 patients (including 4 siblings and 2 second cousins), 3 patients were less than 12 years old at diagnosis of hepatocellular carcinoma, 8 patients were 13-24 years old, and 3 patients were more than 60 years old. Since p53 mutations occur in 29% of hepatocellular carcinomas worldwide, we tested the tumors for p53 mutations and serum samples for anti-p53 antibodies. Serum samples from these 14 patients did not contain detectable levels of anti-p53 antibodies. Loss of heterozygosity within the p53 locus was not detected in any of 9 informative cases. Immunohistochemical analysis for p53 protein accumulation was negative in all of 11 tumors. DNA sequence analysis of 12 tumor samples showed no evidence of p53 mutation in the highly conserved regions included in exons 5-8. These data, combined with one case from a previous report, indicate a mutation frequency of 0 of 13, which differs significantly from the worldwide frequency of 29% (chi 2 3.9; P = 0.048). These results indicate that liver carcinogenesis among Alaska Natives occurs independently of a traditional p53 pathway. The familial clustering and early onset in this population strongly suggest an inherited genetic predisposition to develop liver cancer. Germline mutations in a tumor suppressor or a cancer susceptibility gene are likely. Future studies of these samples should include investigations of candidate suppressor or susceptibility genes which map to chromosomal regions commonly deleted in liver cancers.

Alaska Native cancer update: incidence rates 1989-1993.

Five-year average annual age-adjusted cancer incidence rates for Alaska Natives (Eskimos, Indians, and Aleuts) for the most recent period (1989-1993) are compared to rates of 20 years earlier. Rates for all cancers combined increased 28 and 25% in men and women, respectively, during the 25-year interval. Increases were seen in men in cancers of the lung, prostate, and colon and in women for cancers of the lung, breast, and corpus uteri. Rates are also compared to data from the the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program for United States whites. Rates for all cancers combined in Alaska Native women are now similar to those of United States whites, whereas rates in Alaska Native men are lower than the United States, but only 10% lower. Significant site-specific differences previously reported between Alaska Natives and United States whites persist.

The HLA system in Inupiat and Central Yupik Alaskan Eskimos.

We have studied HLA antigen profiles of the Inupiaq and Yupik-speaking peoples, two of the four Eskimo linguistic groups residing in Alaska. A relatively restricted polymorphism of HLA-A and -B locus antigens was noted. Only 35% of A locus specificities and 37% of B locus specificities tested for were detected in each population. The most common A locus alleles were A2, A24, and A28; the most common B locus alleles were B51(5), B27, B35, Bw60(40), Bw61(40), and Bw62(15). The antigens Cw3 (75 and 69%) and DR4 (81 and 67%) were found in high frequency in both groups. HLA-DR1, DR2, and DR7 were detected infrequently, while DR3 was not detected at all. DR4 was frequently associated in both Inupiats and Yupiks with Dw4, a specificity that was thought to occur only in Caucasian populations. A statistically significant difference between Inupiats and Yupiks was found for polymorphism at the A locus, but no significant differences were found for polymorphisms at the B, C, D, or DR loci. Analysis of HLA linkage disequilibrium revealed the presence of several novel haplotypes not previously described in other populations, suggesting that the selective factors responsible for positive associations observed in these Native Alaskans were probably distinct.

T-cell receptor polymorphisms in Tlingit Indians with rheumatoid arthritis.

Rheumatoid arthritis (RA) develops as a result of the interaction of both genetic and environmental factors. Among the genes in humans that have been suggested as candidate susceptibility genes in RA are those encoding the T cell receptor for antigen (TCR). A high prevalence and early age of onset of RA has previously been reported in Alaskan Tlingit Indians. In this study, the frequency of seven different restriction fragment length polymorphisms (RFLPs) in the TCR alpha and beta gene complexes were measured in a population of Alaskan Tlingit Indians. No statistically significant differences were noted when the frequencies of these RFLPs were compared between Tlingits with RA and healthy controls (p > 0.05). These results do not support the hypothesis of an RA-susceptibility allele in the vicinity of these TCR alpha or beta genes. Since TCR RFLPs have not been extensively studied in native American populations, TCR polymorphism frequencies in the Tlingits were also compared to the frequencies observed in a second control group of healthy Caucasians. Statistically significant differences were observed in these comparisons implying a different distribution of individuals in these populations with different TCR repertoires.

Colorectal cancer incidence and survival among Alaska Natives, 1969-1993.

BACKGROUND: Although colorectal cancer rates are low among most groups of Native Americans in North America, rates for Alaska Natives have been substantially elevated compared with US rates for all races combined. METHODS: To better describe the epidemiology of colorectal cancer incidence and survival among Alaska Natives, stratified by gender and tribal/ethnic affiliation, we examined data collected by the Alaska Native Cancer Registry 1969-1993. We calculated age-adjusted and age-specific incidence as well as actuarial survival rates, and examined histological type, site, stage at diagnosis, and treatment. We compared these data to colorectal cancer data from whites living in western Washington. RESULTS: In all, 587 colorectal cancer cases were identified among Alaska Natives over the 25-year period, for an age-adjusted annual incidence rate of 71.4/100000 in women, and 69.3/100000 in men. Compared to Alaska Indians, colon cancer rates were significantly higher in Aleuts (relative risk [RR] = 1.6, 95% CI: 1.2-2.2) and in Eskimos (RR = 1.5, 95% CI: 1.2-1.8), while rectal cancer rates did not differ by race/ethnicity. Alaska Natives experienced a 50% higher incidence rate of colorectal cancer overall compared to western Washington whites (RR = 1.5, 95% CI: 1.3-1.6), although rectal cancer rates were similar in the two populations. The highest RR were seen among Alaska Native women; Aleuts and Eskimos had colon cancer rates more than twice that of western Washington white women. No unusual qualitative features were found in the cancers occurring in Alaska Natives. Actuarial colorectal cancer survival rates for Alaska Natives overall were 74% at one year and 42% at 5 years; these rates were very similar to those observed for the western Washington population. Both one and 5-year survival rates showed a significant trend towards improvement over time. CONCLUSIONS: Alaska Natives had substantially higher colorectal cancer incidence rates compared to western Washington whites. Rates were particularly high for Aleut and Eskimo women. These data suggest a need for intensified secondary prevention strategies for this high-risk population, while further research is needed to identify modifiable risk factors.

Oesophageal cancer among Alaskan natives, 1955-1981.

Forty-two patients with oesophageal cancer were identified among Alaskan Natives from 1955 through 1981. Based on rates for US whites, there were 1.3 and 3.8 times the number of Native men and women diagnosed with oesophageal cancer as expected. Forty of the patients were Eskimo or Aleut, resulting in an incidence for Eskimo-Aleuts of 10.9 for males and 8.3 for females per 100 000 adjusted to the world standard population. The distribution of cancer patients by residence at diagnosis showed marked regional clustering, which has been observed among oesophageal cancer patients in several other areas of the world.

Increased risk of cancer in siblings of Alaskan native patients with nasopharyngeal carcinoma.

Alaskan Natives (Eskimos, Indians, Aleuts) are at increased risk of developing nasopharyngeal cancer (NPC) and there is family clustering of NPC. This study reviewed the total cancer experience of relatives of NPC patients and found that siblings of Eskimo NPC patients had a nearly threefold risk. No cancer family syndrome was identified and the cancers diagnosed in the siblings were similar to those seen in the general Alaskan Eskimo population.