Between 1990 and 2000, the U.S. Hispanic population increased from 22.3 million to 35.3 million, and by 2050, it is expected that over 97 million Hispanics will live in the United States, accounting for nearly one-fourth of the U.S. population [1, 2]. In the Western United States, the Hispanic presence is much larger (in 2005, Hispanics, primarily originating from Mexico and Central America, comprised 35% of the adult population in California) . Hispanics are a diverse group, varying significantly with regard to country of origin, demographic factors, health-related characteristics and acculturation level including generation in the U.S., and dominant language. In general, Hispanics of Mexican and Central American descent (hereafter referred to as Latinos) are significantly more disadvantaged on many socioeconomic and health measures than those of Cuban, Puerto Rican, or South American descent .
Among Latinos, being born in the US tends to be positively associated with higher educational attainment, higher income, English proficiency  and Internet access , but negatively associated with health-promoting behaviors and chronic health problems . As a result of generational differences, the overall demographic and health characteristics of the Latino population are likely to change substantially as the percentage of the Latino population that is born in the U.S. or immigrate at a very young age increases. The 2002 National Survey of Latinos found that nearly all Latinos born in the U.S. speak English, with 46% of second generation and 22% of third-plus generations being bilingual, compared with only 28% of foreign-born Latinos (24% of whom are bilingual) . Educational attainment is also significantly higher among second and third generation Latinos as compared with foreign-born Latinos, with 75% vs. 46%, respectively, completing at least high school and 14% vs. 9% having college degrees. While Latino adults are significantly less likely than non-Hispanic Whites and African-Americans to use the Internet, English-dominant (prefers to communicate in English) and bilingual Latinos are approximately three times more likely to use the Internet than Spanish-dominant (very limited or no English language proficiency) Latinos, and the difference between English-dominant Latinos and non-Hispanic Whites Latinos significantly diminishes after adjusting for education .
Health behaviors and chronic diseases have also been shown to be subject to the effects of generational differences due to acculturation. Based on evidence of several studies of the effects of acculturation on Latino health behaviors and health, Lara et al posit that the effect of acculturation, while not absolute, is generally negative with regard to health behaviors such as dietary practices, smoking, obesity, and physical inactivity, resulting in an increasing rate of diabetes and onset at younger ages . For example, while studies have found dietary changes that are healthy (e.g., decreased use of lard, cream, and sausage) and unhealthy (e.g., less fresh fruits and vegetables, rice, beans, and more sweets) among more acculturated versus less acculturated Latina women, the researchers judged the overall effect of acculturation on diet to be more negative than positive [7–9]. The effect of acculturation on Latino smoking appears to be gender-dependent; acculturation is associated with increased smoking prevalence among women, but has little or no effect on men. Ultimately, this results in the more acculturated men and women having smoking rates similar to those among non-Hispanic Whites [7, 10, 11]. Three studies found a higher prevalence of obesity among more acculturated Latino adults and adolescents than among the less acculturated [12–14]. In contrast to these negative effects, Crespo et al. found that acculturation was positively associated with participation in leisure-time physical activity .
According to the 2005 California Health Interview Survey, there were approximately 900,000 Latinos of Mexican or Central American descent aged 20–64 covered by non-Medicaid health insurance in California in 2005, approximately 23% of all insured adults in this age group . Of these, approximately 24% had limited ability to speak English, 51% spoke English well or very well, and 25% spoke only English. The objective of our study was to explore the heterogeneity of Spanish-dominant, bilingual, and English-dominant Latinos aged 25–64 who were members of a large Northern California health plan with regard to educational attainment, income, health-related characteristics, access to information technology, and preferred methods for receiving health information and health education. Our intent is to provide information to health plans serving a culturally diverse Latino population with information that might aid in understanding differences in health care needs and outcomes for these populations, as well as for planning health education services.