Cancer mortality in a northeastern native American population

Fifty years of cancer in an American Indian population

BACKGROUND

A clear understanding of cancer patterns among American Indian tribal groups has been complicated by a variety of issues. A retrospective cohort study design was applied to a Seneca Nation of Indians (SNI) cohort for the period from 1955 through 2004.

METHODS

Incident cancers were identified through a computer match with the New York State Cancer Registry. Standardized incidence ratios (SIRs) and 95% confidence intervals were calculated for the overall interval as well as for each of the 5 10-year intervals. The SNI cohort consisted of 3935 men and 4193 women with a total of 120,403 person-years.

RESULTS

Significant deficits in cancer incidence were noted among men for all sites combined (SIR, 69), and for lung (SIR, 59), prostate (SIR, 54), urinary bladder (SIR, 8), and Hodgkin lymphoma (SIR, 0); no cancer sites were identified with significantly elevated incidence. Women demonstrated significantly reduced cancer incidence for all sites combined (SIR, 70) and for breast (SIR, 39), colorectal (SIR, 72), ovary (SIR, 37), uterus (SIR, 42), bladder (SIR, 20), pancreas (SIR, 10), and non-Hodgkin lymphoma (SIR, 39); elevated incidence was noted for cancers of the lung (SIR, 139) and liver (SIR, 405).

CONCLUSIONS

To the authors' knowledge, the current study represents the most comprehensive investigation to date of cancer patterns among an American Indian tribal group and provides insights for the development of tribal cancer control programming.

Oncogenic human papillomavirus infection and cervical lesions in aboriginal women of Nunavut, Canada

BACKGROUND

The high rate of cervical cancer among aboriginal women of northern Canada has prompted the search for more aggressive methods to augment Papanicolaou (Pap) screening in this population. Nearly all cervical cancers result from oncogenic human papillomavirus (HPV) infections. This has generated interest for incorporating HPV testing into the current screening program.

GOALS

To determine the prevalence of oncogenic HPVs in Nunavut, and to assess the association between HPV and squamous intraepithelial lesions (SIL).

STUDY DESIGN

A cross-sectional study was conducted on the Pap-screened populations in 19 communities of Nunavut, Canada. Liquid-based cytology was used to screen for SIL. HPV testing was performed using the Hybrid Capture II assay. Correlates of HPV infection and SIL were assessed by logistic regression with control for potential confounders.

RESULTS

In 1290 women ages 13 to 79 years, the prevalence rate was 26% for oncogenic HPV and 6.9% for SIL. The odds ratio for the association between HPV and SIL was 37.9 (95% CI, 17.7-80.8) after multivariate adjustment. This association increased markedly with increasing viral load. More than 90% of the women with squamous intraepithelial lesions had positive test results for HPV. More than 75% of the women who had positive test results for HPV but negative test results for SIL were younger than 30 years.

CONCLUSION

The results of this study form the basis for further evaluation of the role that liquid-based cytology and HPV testing plays and will contribute to the strategy for cervical cancer prevention in Nunavut.

Cancer incidence among American Indians and Alaska Natives, 1980 through 1987

OBJECTIVES

This study uses Indian Health Service inpatient data to estimate cancer incidence among American Indians and Alaska Natives.

METHODS

Hospital discharge data for 1980 through 1987 were used to identify cases of cancer for 21 sites in women and 18 sites in men. Estimates of incidence were directly standardized to data from the Surveillance, Epidemiology, and End Results Program for the same time frame.

RESULTS

Cancers of the gallbladder, kidney, stomach, and cervix show generally high rates among many American Indian and Alaska Native communities, and cancers of the liver and nasopharynx are high in Alaska. Of the relatively common cancers in Whites, American Indians and Alaska Natives experience lower rates for cancers of the breast, uterus, ovaries, prostate, lung, colon, rectum, and urinary bladder and for leukemia and melanoma. Variation among geographic areas and among tribal groups is observed for many important cancer sites.

CONCLUSIONS

This study demonstrates significant variations of cancer rates among American Indians and Alaska Natives, with important implications for Indian Health Service cancer control programs. The study also supports the potential use of hospital discharge data for estimating chronic disease among diverse American Indian and Alaska Native communities.

Dietary micronutrients and cervical dysplasia in southwestern American Indian women

American Indian women in the Southwest have high rates of cervical cancer and cervical dysplasia in contrast to low rates of cancers for other sites. Despite their high rates of cervical disease, no published information has specifically examined risk factors for cervical cancer or cervical dysplasia among American Indian women. We carried out a pilot case-control study of cervical dysplasia in southwestern American Indian women to examine the relationship of dietary intake of vitamin C, folacin, vitamin E, carotenoids, and retinol with cervical cytological abnormalities. Twenty-four-hour dietary recalls were collected from women with cervical dysplasia (n = 42) and women with normal cervical cytologies (n = 58). Macro- and micronutrient intake was estimated from these recalls utilizing food and nutrient data from the USDA Survey Nutrient Database. Although mean differences between cases and controls were not statistically significant for any of the micronutrients examined, women with low intake of vitamin C, folacin, and vitamin E were at increased risk of having cervical dysplasia when the data were analyzed as stratified for level of intake (low vs. high intake odds ratios were 3.0 for vitamin C, 3.3 for folacin, and 1.7 for vitamin E). The relationship between dietary micronutrients and cervical dysplasia among American Indian women warrants further investigation using more refined measures of dietary micronutrient intake, together with consideration of other risk factors for cervical disease.

Cancer mortality in Native Americans in North Carolina

This paper describes age-adjusted mortality from malignant neoplasms for Native Americans in North Carolina for 1968-72 and 1978-82. Sex-specific standardized mortality ratios were calculated from death certificate data, using the cancer mortality experience of White North Carolinians to obtain the number of expected deaths. For most categories and specific sites of cancer, mortality was at or below the expected level, but higher than expected mortality was found for genitourinary cancers in males (SMR = 1.62, 95% CI = 1.15, 2.21) for the 1978-82 period; within this category, there was a higher than expected level of mortality from prostate cancer (SMR = 2.00; 95% CI = 1.36, 2.83) and cancer of the penis and other male genital organs (SMR = 9.09; 95% CI = 1.10, 32.84). Female Native Americans had an elevated mortality from cervical cancer (SMR = 2.27, 95% CI = 1.09, 4.17) for the 1968-72 period only.