Invasive breast cancer incidence trends by detailed race/ethnicity and age

Racial/ethnic disparities in breast cancer incidence may contain important evidence for understanding and control of the disease. Monitoring the incidence trends of breast cancer by race/ethnicity allows identification of high risk groups and development of targeted prevention programs. Using population-based cancer registry data from the Los Angeles Cancer Surveillance Program, we examined the invasive female breast cancer incidence trends among the diverse racial/ethnic populations in Los Angeles County, California, from 1972 to 2007. Age-adjusted incidence rates (AAIRs) and age-specific incidence rates (ASIRs) were calculated and examined respectively for non-Hispanic (NH) white, black, Hispanic, Chinese, Filipina, Japanese and Korean women by calendar year and time period. Rising trends of AAIRs were found in all racial/ethnic groups during the 1980s and 1990s. The breast cancer risk increased more substantially in Japanese and Filipinas than in Chinese and Koreans. During 2000-2007, the trends of AAIRs declined significantly among NH white women and slightly in blacks, remained unchanged for Hispanics and continued to rise significantly among all Asian subgroups. The patterns of ASIRs by race/ethnicity changed dramatically over time. By 2000-2007, younger Hispanic women had the lowest breast cancer risk, replacing the Chinese and Koreans who formerly had the lowest risk. Rapidly increasing breast cancer incidence trends among Asian-Americans underline the importance of behavioral and lifestyle changes as a result of acculturation on the development of the disease. The unique trends of breast cancer incidence by race/ethnicity suggest the need for targeted breast cancer control programs for different racial/ethnic populations.     

Race/Ethnicity and Changing US Socioeconomic Gradients in Breast Cancer Incidence: California and Massachusetts, 1978–2002 (United States)

OBJECTIVE: We tested the hypothesis that the US socioeconomic gradient in breast cancer incidence is declining, with the decline most pronounced among racial/ethnic groups with the highest incidence rates. METHODS: We geocoded the invasive incident breast cancer cases for three US population-based cancer registries covering: Los Angeles County, CA (1978-1982, 1988-1992, 1998-2002; n = 68,762 cases), the San Francisco Bay Area, CA (1978-1982, 1988-1992, 1998-2002; n = 37,210 cases) and Massachusetts (1988-1992, 1998-2002; n = 48,111 cases), linked the records to census tract area-based socioeconomic measures, and, for each socioeconomic stratum, computed average annual breast cancer incidence rates for the 5-year period straddling the 1980, 1990, and 2000 census, overall and by race/ethnicity and gender. RESULTS: Our findings indicate that the socioeconomic gradient in breast cancer incidence is: (a) relatively small (at most 1.2) and stable among US white non-Hispanic and black women; (b) sharper and generally increasing among Hispanic and Asian and Pacific Islander American women; and (c) cannot be meaningfully analyzed without considering effect modification by race/ethnicity and immigration. CONCLUSION: Our results indicate that secular changes in US socioeconomic gradients in breast cancer incidence exist and vary by race/ethnicity.     

Cancers of the prostate and breast among Japanese and white immigrants in Los Angeles County

Using age-adjusted incidence rates and proportional incidence ratios, the risks of prostate cancer and breast cancer in three racial/ethnic groups - Spanish-surnamed whites, other whites and Japanese - were studied in Los Angeles County native residents and compared with those in immigrants and representative 'homeland' populations. An algorithm based on social security numbers was developed and utilised to estimate age at immigration for non-US-born Los Angeles County cancer patients. For prostate cancer, the incidence rates in Los Angeles County were much higher than those in the homelands for each racial/ethnic group. However, prostate cancer rates of immigrants were similar to those of US-born patients in the Spanish-surnamed white and Japanese populations, regardless of age at immigration. For breast cancer, the incidence rates in Los Angeles County were also high compared with those in the homelands. However, the timing of immigration to the US was important in determining breast cancer risk. When social security numbers indicated that migration occurred later in life, rates for breast cancer were substantially lower than when migration occurred early, although they were still much higher than in the homeland populations. These findings suggest that environmental factors in early life rather than in later life are important in the etiology of breast cancer and that later life events can substantially impact the likelihood of developing clinically detectable prostate cancer.     

Decreased chronic lymphocytic leukemia incidence in Asians in Los Angeles County

Chronic lymphocytic leukemia (CLL) is rare in Asians living in Asia and possibly in US Asians. In contrast, CLL is the most common leukemia in whites. The basis for this ethnic and geographic variation is unknown. We compared average annual age-adjusted incidence rates (AAIR) of CLL diagnosed from 1972 to 1995 among Los Angeles County-resident Asians, non-Spanish-surnamed- and Spanish-surnamed whites (non-Hispanic and Hispanic-whites) and blacks using the University Southern California-Cancer Surveillance Program (USC-CSP), the population-based cancer registry for Los Angeles County. Asian groups studied included Chinese, Japanese, Filipinos and Koreans. Expected numbers of CLL cases were based on the age-adjusted incidence rates in non-Hispanic whites and compared to numbers of cases observed in Chinese, Japanese and Filipinos. Possible association of socioeconomic state (SES) was assessed using AAIRs with SES-specific denominators. In the absence of denominators by birthplace, the association of birthplace and CLL-incidence was evaluated using proportional odds ratios (POR). Los Angeles County Asian males and females had significantly lower AAIRs than non-Hispanic whites (males: AAIR=0.7 per 100000 population, 95% confidence interval (CI), 0.5-1.0 vs. 4.4, 95% CI, 4.3-4.6; and females: AAIR=0.5, 95% CI, 0.3-0.7 vs. 2.3, 95% CI, 2.2-2.4). Fewer Japanese Chinese and Filipinos were diagnosed with CLL than expected (P<0.01). There was no association of birthplace (POR=0.9, 95% CI, 0. 5-1.9) or SES on CLL-risk. CLL-risk was markedly lower in Los Angeles County Asians compared to non-Hispanic whites. Neither birthplace nor socioeconomic state accounted for this difference suggesting a role for genetic or other environmental factors in decreasing CLL-risk.     

Menstrual and reproductive factors and risk of breast cancer in Asian-Americans.

We conducted a population-based case-control study of breast cancer among Chinese-, Japanese- and Filipino-American women in Los Angeles County Metropolitan Statistical Area (MSA), San Francisco-Oakland MSA and Oahu, Hawaii. One objective of the study was to quantify breast cancer risks in relation to menstrual and reproductive histories in migrant and US-born Asian-Americans and to establish whether the gradient of risk in Asian-Americans can be explained by these factors. Using a common study design and questionnaire in the three study areas, we successfully conducted in-person interviews with 597 Asian-American women diagnosed with incident, primary breast cancer during the period 1983-87 (70% of those eligible) and 966 population-based controls (75% of those eligible). Controls were matched to cases on age, ethnicity and area of residence. In the present analysis, which included 492 cases and 768 controls, we observed a statistically non-significant 4% reduction in risk of breast cancer with each year delay in onset of menstruation. Independent of age at menarche risk of breast cancer was lower (odds ratio; OR=0.77) among women with menstrual cycles greater than 29 days. Parous Asian-American women showed a significantly lower risk of breast cancer then nulliparous women (OR=0.54). An increasing number of livebirths and a decreasing age at first livebirth were both associated with a lower risk of breast cancer, although the effect of number of livebirths was no longer significant after adjustment for age at first livebirth. Women with a pregnancy (spontaneous or induced abortions) but no livebirth had a statistically non-significant increased risk (OR=1.84), but there was no evidence that one type of abortion was particularly harmful. A positive history of breastfeeding was associated with non-significantly lower risk of breast cancer (OR=.78). There are several notable differences in the menstrual and reproductive factors between Asian-Americans in this study and published data on US whites. US-born Asian Americans had an average age at menarche of 12.12 years-no older than has been found in comparable studies of US whites, but 1.4 years earlier than Asian women who migrated to the US. Asian-American women, particularly those born in the US and those who migrated before age 36, also had a later age at first birth and fewer livebirths than US whites. A slightly higher proportion of Asian-American women breastfed, compared with US whites. The duration of breastfeeding was similar in US-born Asians and US whites, but was longer in Asian migrants, especially those who migrated at a later age. Menstrual and reproductive factors in Asian-American women are consistent with their breast cancer rates being at least as high as in US whites, and they are. However, the effects of these menstrual and reproductive factors were small and the ORs for migration variables changed only slightly after adjustment for these menstrual and reproductive factors. These results suggest that the lower rates of breast cancer in Asians must be largely as a result of other environmental/lifestyle factors.     

Tea intake, COMT genotype, and breast cancer in Asian-American women

There is substantial in vitro and in vivo evidence implicating tea polyphenols as chemopreventive agents against various cancers. In a case-control study conducted among Asian-American women in Los Angeles County, we reported a significant inverse relationship between intake of green tea and risk of breast cancer (A. H. Wu et al., Int. J. Cancer, 106: 574-579, 2003). Because catechol-containing tea polyphenols are very rapidly O-methylated by human catechol-O-methyltransferase (COMT), we are interested in determining whether the association between tea intake and breast cancer differed in women according to COMT genotype. We examined the interrelationships between tea intake, COMT genotype, and breast cancer risk in 589 incident cases and 563 population-based controls from a population-based case-control study of breast cancer in Chinese-, Japanese-, and Filipino-American women in Los Angeles County. Risk of breast cancer was influenced significantly by intake of tea, particularly green tea intake. However, the inverse association between tea intake and breast cancer risk was observed only among individuals who possessed at least one low-activity COMT allele. Among women who carried at least one low activity COMT allele, tea drinkers showed a significantly reduced risk of breast cancer (adjusted odds ratio, 0.48; 95% confidence interval, 0.29-0.77) compared with nontea drinkers after adjustment for relevant demographic, menstrual, reproductive, and dietary factors. This risk reduction was observed in relation to both green tea and black tea intake. In contrast, risk of breast cancer did not differ between tea drinkers and nontea drinkers among those who were homozygous for the high activity COMT allele (adjusted odds ratio, 1.02; 95% confidence interval, 0.66-1.60). In conclusion, tea catechins appeared to reduce breast cancer risk in this study of Asian-American women. Reduction in risk was strongest among persons who had the low activity COMT alleles, suggesting these individuals were less efficient in eliminating tea catechins and may derive the most benefit from these compounds.     

Physical activity and breast cancer risk among Asian-American women in Los Angeles: a case-control study

BACKGROUND: To the authors' knowledge, there have been few studies published to date regarding physical activity patterns and breast cancer risk in Asian and Asian-American women. METHODS: The authors conducted a population-based case-control study of 501 Asian-American women with incident breast cancer and a control group of 594 Asian-American women in Los Angeles County to evaluate the role of lifetime physical activity on breast cancer risk. Information concerning lifetime recreational physical activity (i.e., type of activity, duration [years], and frequency [average hours per week]) and occupational physical activity was obtained using a structured questionnaire that was administered in person. RESULTS: Increasing years and levels (average metabolic equivalent [MET] hours per week) of lifetime recreational activity were associated with a significantly reduced risk of breast cancer after adjusting for demographic factors, migration history, and menstrual and reproductive factors. Compared with women who had no lifetime recreational physical activity, 3-6 MET hours per week, > 6-12 MET hours per week, and > 12 MET hours per week of activity were associated with significantly reduced risk, with odds ratios (and 95% confidence intervals) of 0.91 (0.55-1.49), 0.65 (0.39-1.10), 0.53 (0.31-0.90), and 0.47 (0.28-0.80), respectively (P value for trend < 0.001). The risk of breast cancer was associated inversely with occupational physical activity, although the result was not statistically significant. CONCLUSIONS: The findings of the current study provide further support for the finding that physical activity has a protective role in breast cancer.     

Prostate cancer: trends in mortality and stage-specific incidence rates by racial/ethnic group in Los Angeles County,California (United States)

Between 1976 and 1988 in the United States, the secular trends in age-adjusted incidence rates of prostate cancer were significantly different by racial/ethnic group (P<0.001), and increased significantly only among non-Hispanic Whites at a rate of 2.7 percent (95 percent confidence interval [CI]=2.3–3.1%) annually. While incidence rates of regional disease increased significantly (7.7 percent to 11.3 percent annually) among all racial/ethnic groups during this period, localized disease increased significantly only among non-Hispanic Whites, by 1.8 percent (CI=1.4–2.3%) annually. Prostate cancer mortality in Los Angeles County (California) remained constant among Hispanics, non-Hispanic Whites, and Asians, but increased 1.6 percent (CI=0–3.2%) annually among Blacks. While the increase in localized disease rates of non-Hispanic Whites may be due to increased detection of asymptomatic disease, this apparently has not occurred among other racial/ethnic groups in Los Angeles County. The secular increase in regional disease rates among all racial/ethnic groups without a concurrent increase in mortality (except Blacks), suggests increased accuracy of staging rather than a true increase in incidence may account for these trends. Adjusted for socioeconomic status, year and age at diagnosis, Black and Hispanic men were at significantly higher risk of being diagnosed with non-localized disease (odds ratio = 1.39 and 1.24, respectively) than were non-Hispanic Whites.Drs Ross and Bernstein are also with the Cancer Surveillance ProgramThis work was supported in part by grant CA17054 from the US National Institutes of Health, and grant SIG#20 from the American Cancer Society. Cancer incidence data were collected under Subcontract 050H-8709 with the California Public Health Foundation. The subcontract is supported by the California Department of Health Services as part of its statewide cancer reporting program, mandated by Health and Safety Code Section 210 and 2113.     

Smoking-adjusted Lung Cancer Incidence Among Asian-Americans (United States)

Objective:Chinese women residing in Asia and Hawaii have low consumption of tobacco but a high incidence of lung cancer. To explore this question further, we conducted a study of lung cancer among Chinese women residing in mainland US. Methods:Using data from NCI’s SEER program, we identified residents of Los Angeles County, the San Francisco Metropolitan Area, and the Seattle-Puget Sound Area who were 50 years or older, diagnosed with cancer of the lung or bronchus in 1999–2001, with race specified as non-Hispanic white (n = 18,493), Chinese (n = 853), Filipino (n = 615), or Japanese (n = 282). The sex-specific observed number of lung cancer cases among each Asian sub-group was compared to the expected number of lung cancer cases for each Asian sub-group. The expected number was determined by multiplying the age-, sex-, and geographic area-adjusted incidence rates for non-Hispanic whites by the age- and sex-specific ratio of percentage of current smokers in each Asian sub-group to whites in 1990, and then by the size of the respective Asian populations. Results: Chinese women had a four-fold increased risk of lung cancer, and Filipino women a two-fold increased risk, compared to that expected based on rates in US non-Hispanic whites with a similar proportion of cigarette smokers. Lung cancer among Chinese, Filipino, and Japanese males, as well as Japanese females, did not deviate from expected risk. Among Chinese women, the increased risk was largely restricted to adenocarcinoma and large cell undifferentiated carcinoma. Conclusions: Chinese female residents of the western US mainland have a much higher risk of lung cancer than would be predicted from their tobacco use patterns, just as they do in Asia.     

A trend analysis of breast cancer incidence rates in the United States from 2000 to 2009 shows a recent increase

Recent reports have shown that the breast cancer incidence rate in the US stabilized after a sharp reduction in 2002 and 2003. It is important to continue monitoring breast cancer incidence rates according to age group, race/ethnicity, estrogen receptor (ER) status, and tumor stage. Age-standardized breast cancer incidence rates were calculated using data from the surveillance, epidemiology, and end results 18 registries from 2000 to 2009, for 677,774 female breast cancer patients aged 20 and above. Jointpoint regression models were used to fit a series of joined straight lines on a log scale to annual age-standardized rates. The incidence rates of all breast cancer significantly increased for non-Hispanic blacks from 2005 to 2009 (annual percentage change, APC = 2.0 %, p = 0.01) and Asian/Pacific Islanders from 2000 to 2009 (APC = 1.2 %, p = 0.02). Since 2004, incidence rates in women aged 40–49 years significantly increased for most racial/ethnic groups (overall APC = 1.1 %, p = 0.001). The incidence rate of carcinoma in situ significantly increased in all racial/ethnic groups, with an APC range from 2.3 to 3.0 % (p < 0.005). The localized breast cancer incidence significantly increased in non-Hispanic blacks (APC = 1.3 %, p = 0.004) and Asians (APC = 1.2 %, p = 0.03). ER-positive breast cancer significantly increased in almost all age/race sub-groups after 2005 (APC by race: non-Hispanic whites 1.5 %, non-Hispanic blacks 4.3 %, Asian/Pacific Islanders 1.7 %, and Hispanics 1.8 %; all p values <0.05), while ER-negative breast cancer decreased in most sub-groups (APC by race: non-Hispanic whites—3.9 %, non-Hispanic blacks—3.7 %, Asian/Pacific Islanders—1.5 %, and Hispanics—4.3 %; all p values <0.05). Recently the incidence of breast cancer appears to be increasing in certain subgroups, including ER-positive, early-stage breast cancers, in particular among non-Hispanic blacks and Asian/Pacific Islanders. Further studies are warranted to examine possible reasons for these changes, such as changes in mammography screening methods and risk factors prevalence.     

Socioeconomic status and breast cancer incidence in California for different race/ethnic groups

Objective: The majority of research on breast cancer risk and socioeconomic status (SES) has been conducted for blacks and whites. This study evaluates the relationship between SES and breast cancer incidence in California for four race/ethnic groups. Methods: Principal component analysis was used to create an SES index using 1990 Census data. Untracted cases were randomly allocated to census block groups within their county of residence. A total of 97,227 female breast cancer cases diagnosed in California between 1988 and 1992 were evaluated. Incidence rates and rate ratios (RRs) were estimated and a ² test for trend across SES levels was performed. Results: SES was positively related to breast cancer incidence, and this effect was stronger for Hispanics and Asian/others than for whites and blacks. Adjusting by SES did not eliminate the differences in breast cancer rates among race/ethnic groups. RR differences between the race/ethnic groups were greatest in the lowest SES category and attenuated with increasing SES. An increasing trend over SES was statistically significant for all race/ethnic groups. Including randomly allocated cases affected RR estimates for white women only. Conclusions: Our results are consistent with similar findings for the Los Angeles area but differ from previous results for the San Francisco Bay area.     

Geographic Patterns of Advanced Breast Cancer in Los Angeles: Associations with Biological and Sociodemographic Factors (United States)

Objective Examination of patterns of advanced breast cancer may provide evidence needed to direct health care resources to those communities or population groups in greatest need. We assessed to what degree biologic, ethnic, and sociodemographic factors could explain such patterns within Los Angeles County. Methods The proportion of cases of advanced disease among all breast cancer cases identified during 1992–1996 were analyzed using generalized linear mixed models with random census tract effects. Models included characteristics of the individual and her tumor, census tract of residence, and aggregated health districts. Results Approximately 6% of cases, ranging from 4% for Asian to 10% for Black women, were diagnosed as advanced, exhibiting striking geographic patterns. Tumor histology and hormone receptor status were most predictive of advanced disease. Sociodemographic variables such as marital status, median income, and distance to nearest mammography unit showed additional association with risk. Conclusions These models explain most of the geographical patterns and eliminate differences between White and Hispanic but not Asian or Black women, identify subpopulations at high risk of advanced disease, and suggest cancer control opportunities.     

Metabolic conditions and breast cancer risk among Los Angeles County Filipina Americans compared with Chinese and Japanese Americans

Accumulating evidence suggests that the aggregation of common metabolic conditions (high blood pressure, diabetes and dyslipidemia) is a risk factor for breast cancer. Breast cancer incidence has risen steadily in Asian American women, and whether these metabolic conditions contribute to breast cancer risk in certain Asian American subgroups is unknown. We investigated the role of physician‐diagnosed hypertension, high cholesterol and diabetes separately, and in combination, in relation to the risk of breast cancer in a population‐based case–control study of 2,167 Asian Americans diagnosed with breast cancer and 2,035 age and ethnicity matched control women in Los Angeles County. Compared to Asian American women who did not have any of the metabolic conditions, those with 1, 2 or 3 conditions showed a steady increase in risk (respective odds ratios were 1.12, 1.42 and 1.62; P trend = 0.001) with adjustment for covariates including body mass index. Similar significant trends were observed in Filipina Americans (P trend = 0.021), postmenopausal women (P trend =0.001), Asian women who were born in the United States (US) (P trend = 0.052) and migrants who have lived in the US for at least 20 years (P trend = 0.004), but not migrants who lived in the US for <20 years (P trend = 0.64). These results suggest that westernization in lifestyle (diet and physical inactivity) and corresponding increase in adiposity have contributed to the rising prevalence of these metabolic conditions, which in turn, are associated with an increase in breast cancer.     

Body size, hormone therapy and risk of breast cancer in Asian-American women

Historically, breast cancer rates have been low in Asia but rates have increased substantially in Asian-Americans for reasons that are not well understood. The authors conducted a population-based case-control study of breast cancer in Los Angeles County, which included 1,277 (450 Chinese, 352 Japanese, 475 Filipinos) women with incident, histologically confirmed breast cancer and 1,160 control subjects (486 Chinese, 311 Japanese, 363 Filipinos). A detailed in-person interview was conducted, which included questions on menopausal hormone therapy (HT) use, height, weight in each decade of life and reproductive factors. Breast cancer risk increased with increasing recent weight in postmenopausal women (p trend = 0.015). There was a significant 16% (95% CI = 2-35%) increase in risk per 10 kg of body weight in postmenopausal women. In both premenopausal and postmenopausal women, risk increased with increasing waist to hip ratio; this remained statistically significant after adjustment for recent weight in all subjects combined (p trend = 0.042). The increased risk associated with high recent weight in postmenopausal women was more apparent for women with high waist to hip ratio (p trend = 0.013). Use of HT was a significant risk factor; risk increased 26% per 5 years of current use of estrogen and progestin therapy (p trend = 0.017). The increased risk associated with high body weight was observed irrespective of HT use. Use of HT and high body size might have contributed to the rapid increase of breast cancer in Asian-Americans.     

Cancer incidence, mortality, and associated risk factors among Asian Americans of Chinese, Filipino, Vietnamese, Korean, and Japanese ethnicities

Many studies demonstrate that cancer incidence and mortality patterns among Asian Americans are heterogeneous, but national statistics on cancer for Asian ethnic groups are not routinely available. This article summarizes data on cancer incidence, mortality, risk factors, and screening for 5 of the largest Asian American ethnic groups in California. California has the largest Asian American population of any state and makes special efforts to collect health information for ethnic minority populations. We restricted our analysis to the 4 most common cancers (prostate, breast, lung, colon/rectum) and for the 3 sites known to be more common in Asian Americans (stomach, liver, cervix). Cancer incidence and mortality were summarized for 5 Asian American ethnic groups in California in order of population size (Chinese, Filipino, Vietnamese, Korean, and Japanese). Chinese Americans had among the lowest incidence and death rate from all cancer combined; however, Chinese women had the highest lung cancer death rate. Filipinos had the highest incidence and death rate from prostate cancer and the highest death rate from female breast cancer. Vietnamese had among the highest incidence and death rates from liver, lung, and cervical cancer. Korean men and women had by far the highest incidence and mortality rates from stomach cancer. Japanese experienced the highest incidence and death rates from colorectal cancer and among the highest death rates from breast and prostate cancer. Variations in cancer risk factors were also observed and were for the most part consistent with variations in cancer incidence and mortality. Differences in cancer burden among Asian American ethnic groups should be considered in the clinical setting and in cancer control planning.     

Plasma isoflavone levels versus self-reported soy isoflavone levels in Asian-American women in Los Angeles County

In a case-control study conducted among Asian-American women in Los Angeles County, we reported that the risk of breast cancer was significantly reduced in association with soy intake [Wu,A.H., Wan,P., Hankin,J. et al. (2002) Carcinogenesis, 23, 1491-1496]. In a subset of cases (n = 97) and controls (n = 97) we investigated the relationship between self-reported usual adult intake of soy isoflavones which was determined from a food frequency questionnaire and levels of plasma isoflavones (genistein and daidzein) and isoflavone metabolites (equol, dihydrogenistein and dihydrodaidzein) from a randomly timed blood specimen. In analyses conducted in cases and controls separately, levels of plasma genistein, daidzein and total isoflavones increased with increasing levels of self-reported intake of soy isoflavones. Breast cancer cases and control subjects did not differ in their respective associations between total plasma isoflavone levels and self-reported intake (P = 0.48). Among all subjects, there was a 3-fold difference in geometric mean plasma levels of total isoflavones [81.8 (95% CI = 53.4, 125.1) versus 26.4 nmol/l (95% CI = 16.6, 41.8)] between women in the highest quartile of soy isoflavone intake (>12.68 mg isoflavones/1000 kcal) compared with those in the lowest quartile of intake (相似文献   

Mammographic density and breast cancer in three ethnic groups.

The extent of radiodense tissue on a mammogram (mammographic densities) is strongly associated with breast cancer risk among (non-Latina) white women, but few data exist for African-American and Asian-American women. We collected prediagnostic mammograms from 622 breast cancer patients and 443 control subjects ages 35-64 years from three different ethnic groups (whites, African Americans, and Asian Americans) who participated as cases and controls in one of two ongoing breast cancer studies. Percent and absolute mammographic density were assessed using a previously validated computer-assisted method. In all three ethnic groups combined, breast cancer risk increased with increasing percent mammographic density. After adjustment for ethnicity, age, body mass index, age at menarche, breast cancer family history, age at and number of full-term pregnancies, menopausal status, and hormone replacement therapy use, women with the highest percent density had 5-fold greater breast cancer risk than women with no density (P(trend) = 0.0001). The impact of percent density on risk was stronger for older than for younger women (>/=50 versus <50 years; P = 0.05). Risk estimates did not differ significantly by ethnicity, with breast cancer risk (95% confidence interval) increasing 15% (4-27%) in whites, 30% (5-61%) in Asian Americans, and 11% (-2-26%) in African Americans for each 10% increase in density. The trends were similar for absolute density. Our results confirm that increases in computer-assisted mammographic density measurements are associated with a strong gradient in breast cancer risk. Furthermore, our findings suggest that mammographic density is as strong a predictor of risk for African-American and Asian-American women as for white women.     

Socioeconomic status and cancers of the female breast and reproductive organs: a comparison across racial/ethnic populations in Los Angeles County, California (United States)

Objectives: Despite the fact that socioeconomic status (SES) has been shown to have important implications in health related issues, population-based cancer registries in the United States do not routinely collect SES information. This study presents a model to estimate the SES of cancer patients in the registry database.Methods: At the Los Angeles Cancer Surveillance Program (CSP), we developed a model to estimate each cancer patient's SES from aggregate measurements of the census tract of residence (n = 1,640) at time of diagnosis. We then applied the SES estimates to observe the relationship between SES and risk of cancers of the female breast and reproductive organs including cancers of the ovary, cervix uteri, and corpus uteri. The analyses were performed on the cumulative records (n = 127,819) of cancer patients diagnosed between 1972 and 1992 in Los Angeles County, California, for the mutually exclusive racial/ethnic groups of non-Hispanic Whites, Hispanic Whites, Blacks, Asians, and persons of other ethnic groups.Results: We found SES is positively associated with female breast cancer, ovarian cancer, and cancer of the corpus uteri, but inversely associated with cervical cancer. These SES trends were quite consistent across age groups among non-Hispanic White women. Variations by race/ethnicity in the SES patterns were also found, with Asians exhibiting little association.Conclusions: Our model of measuring SES is sufficiently sensitive to capture the trends. Adopting the aggregate approach to measure SES in population-based registry data appears to be useful.