Richard C. Yang

Cancer incidence in the Hmong in California, 1988-2000

The Hmong represent a unique new Southeast Asian immigrant group to the U.S. Approximately 169,000 Hmong reside in the U.S., primarily in California, Minnesota, and Wisconsin. Previous studies of cancer in this population have indicated that Hmong experience an elevated risk of gastric, hepatic, cervical, and nasopharyngeal cancers and experience a reduced risk of breast, prostate, lung, and colorectal cancers. Approximately 65,000 Hmong live in California, where there has been a population‐based cancer registry since 1988, and the authors used these data to calculate age‐adjusted cancer incidence rates and to examine disease stage and tumor grade at diagnosis. Changes in rates during the period studied also were evaluated. These rates and proportions were compared with rates among the non‐Hispanic white (NHW) and Asian/Pacific Islander (API) populations of California. Between 1988 and 2000, a total of 749 Hmong in California were diagnosed with invasive cancer, and the age‐adjusted rate of cancer for the Hmong was 284 per 100,000 population, compared with 362.6 and 478 per 100,000 in the API and NHW populations, respectively. The age‐adjusted incidence rates of cancer in the Hmong were elevated for hepatic, gastric, cervical, and nasopharyngeal cancers and for leukemia and non‐Hodgkin lymphoma (NHL). Rates were lower in the Hmong for colorectal, lung, breast, and prostate cancers. For gastric cancer and lung cancer, age‐adjusted rates increased between 1988 and 2000 in the Hmong, although breast cancer incidence declined. Cervical cancer incidence increased, rates of NHL were declining, and rates for colorectal cancer remained steady between 1988 and 2000. The Hmong experienced later disease stage at diagnosis than other API and generally poorer grade of disease at diagnosis. Hmong experienced lower overall invasive cancer incidence rates than API or NHW populations in California. However, they experienced higher rates of hepatic, gastric, cervical, and nasopharyngeal cancers; and, for most types of cancer, they were diagnosed in a later disease stage. Cancer 2005.

Breast Cancer Risk in Hispanic Agricultural Workers in California

Abstract In a registry-based case-control study/of breast cancer in farm labor union members in Qalifornia, 128 breast cancer (BC) cases newly diagnosed in 1988-2001 and 640 cancer-free controls were investigated. Stage and grade of disease at diagnosis were about the same asin the California Hispanic population. Risk of breast cancer was not associated with work with any specific crops or commodities except mushrooms, where the adjusted odds ratio (OR) was 6.00 (95% CI 2.01–18.0) Controlling for covariates, adjusted ORs (and 95% CIs) for breast cancer in quartiles of pesticide use were 1.00, 1.30 (0.73–2.30), 1.23 (0.67–2.27), and 1.41 (0.66–3.02). Chlordane, malathion, and 2,4-D were associated with increased risk. Risk associated with chemical use was stronger in younger women, those with early-onset breast cancer, and those diagnosed earlier (1988–1994).

Cancer incidence in the Hmong of Central California, United States, 1987-94

The Hmong are an ethnic minority in China, some of whom migrated tothe mountainous areas of North Vietnam, Laos, and Thailand in the 19th and20th centuries. Because of their support for the United States during theVietnam war, many Laotian Hmong fled to Thailand and eventually werere-settled in the US after the end of that conflict. Approximately100,000Hmong currently live in the US, of whom about half reside in theCentral Valley of California. The purpose of this study was to measure cancerincidence in this unique new immigrant population. Using the resources of theCancer Registry of Central California (CRCC), a population-based cancerregistry, cancer incidence in the Hmong was evaluated by calculatingage-adjusted incidence rates as well as by calculating proportional incidenceratios. Compared with all races combined, elevated rates of cancer in theHmong were observed for the following sites: nasopharynx, stomach, liver,pancreas, leukemia, and non-Hodgkin’s lympho ma. Cervical cancer incidenceoverall was elevated, but more noteworthy, invasive cervix cancer rates weremuch higher than expected. Lower cancer rates were found for breast,prostate, and colorectal cancer. Hmong also experienced advanced stage andgrade of disease at diagnosis for many cancer sites in addition to cervicalcancer, which may be explained by cultural factors, including avoidance ofWestern medical care and low rates of participation in screening programs.This population should be followed closely and monitored for patterns ofcancer incidence in the future since it provides a natural laboratory forstudies of cancer etiology as this population gradually becomes acculturatedto the Western lifestyle.

Cancer in Migrant and Seasonal Hired Farm Workers

ABSTRACT Studies of cancer among farm workers are difficult to conduct and interpret given the unique nature of this occupational group. The transitory nature of the work, high levels of poverty, and lack of legal documentation make epidemiologic studies difficult to accomplish. Nevertheless, this workforce in the United States, which numbers as much as 3 million persons, is a high isk population due to exposures to numerous toxic substances, including excessive sunlight, heat, dangerous machinery, fumes, fertizers, dust, and pesticides. We summarize characteristics of farm workers (i.e., demographics, health care) from the National Agricultural Workers Survey (NAWS) and the California Agricultural Workers Survey (CAWS) and present findings from a series of studies conducted among farm workers in California. The epidemiology literature was reviewed and methods for a unique farm worker union-based epidemiologic study are presented. Farm workers in California and the rest of the United States, many of whom are seasonal and migrant workers are at elevated risk for numerous forms of cancer compared to the general population and specific pesticides may be associated with this altered risk. Elevated risks have been found for lymphomas and prostate, brain, leukemia, cervix, and stomach cancers.

Dietary and Lifestyle Practices of Hmong in California

As Hmong adapt to life in Fresno, California, their dietary and lifestyle patterns are examined. Data on tobacco and alcohol use, dietary practices, and socio-demographic variables were collected from a convenience sample, stratified by age and sex. The 248 participants were interviewed. Descriptive analyses reveal that more than 63% of Hmong adults were either overweight or obese. Only 57% could speak English fluently, and 71% were economically impoverished. Hmong do not consume tobacco and alcoholic products excessively. Rice, chicken, beef, and eggs were the most frequently identified food items. Fruits and vegetables were also identified. Low alcohol and tobacco consumption may offer Hmong some protection against certain diseases. However, low socioeconomic status and rapid urbanization may have resulted in a shift from a high-energy expenditure lifestyle and high fiber diets to a sedentary lifestyle with high saturated fat food diets, which may be detrimental to the health of many Hmong.

Gastric adenocarcinoma among Hmong in California, USA, 1988–2000

BackgroundThis study examined gastric adenocarcinoma incidence, mortality, and tumor characteristics in the Hmong population of California, 1988–2000. Many Hmong relocated to the United States at the conclusion of the Vietnam War. Resettlement difficulties encountered by Hmong have included socioeconomic and healthcare issues. Hmong are wary of Western medicine and would resort to it as the last option, which may delay the diagnosis and treatment of diseases such as cancer.MethodsData from the California Cancer Registry were used to calculate incidence and mortality rates for Hmong, and were compared to these in Asian Pacific Islanders (API) and non-Hispanic whites (NHW). The population at risk was estimated through linear interpolation, using data from the 1990 and 2000 decennial censuses.ResultsHmong experienced incidence and mortality rates of gastric adenocarcinoma several times higher than those of API and NHW. More than 97% of Hmong patients chose no treatment, compared to only 25.6% of API and 30.3% of NHW patients. Hmong were more likely to be diagnosed with cancer at later stages but at better histologic grades than API and NHW.ConclusionsFurther investigations into Helicobacter pylori, Epstein-Barr virus, acid reflux, and dietary practices of Hmong living in the United States are needed before any firm conclusion can be made, as these risk factors may impact gastric cancer development. Hmong should also be encouraged to use traditional and Western medicines simultaneously, provided that traditional healthcare practices do not interfere with biomedicines.