| Epidemiological risk factors for a disease could | | | | Current studies point out that its rate in Japan is |
| give significant clues as to the etiology, or cause, | | | | increasing, coincident with the westernization of |
| of a disease. | | | | the Japanese lifestyle. In general, the incidence of |
| The etiology of human breast cancer remains | | | | breast cancer in American Indian and Alaskan |
| largely unknown. Risk factors associated with the | | | | Native women has been lower than in most of |
| disease could be classified into three extensive | | | | the other racial/ethnic groups in the United States. |
| determinants: family history factors, hormonal and | | | | Migration of these Native American families has |
| reproductive factors, and environmental factors. | | | | caused an upsurge in the rates. |
| A current epidemiologic analysis concluded that | | | | An elevated occurrence of breast cancer has |
| 73% of breast cancers are attributable to | | | | been noted in the U.S. northeast, particularly the |
| environmental factors. Over 78% of cases | | | | New York-New Jersey-Pennsylvania area, which is |
| happen in postmenopausal women. Late onset is | | | | amongst the most heavily polluted areas on the |
| consistent with the long latency periods usually | | | | continent in terms of industrial and vehicular |
| related with chemical carcinogenesis in humans. | | | | emissions. An increased risk of breast cancer was |
| Studies of migrant populations and geographic | | | | reported for postmenopausal women as well who |
| variations in incidence of breast cancer | | | | lived for more than 10 years near an industrial |
| recommend that lifestyle and environmental | | | | facility in Long Island, New York. |
| effects are involved in the etiology of the disease. | | | | While the association of numerous risk factors, |
| Its rates in Asian and Mediterranean countries are | | | | like family history and reproductive patterns, with |
| considerably lower than in North America, yet, in | | | | breast cancer has been well established for |
| some generations, its rate in female offspring of | | | | several years, work in the past 10-15 years has |
| Asian immigrants to the United States approaches | | | | added considerably to our comprehension of |
| the American rate. | | | | disease etiology too. |