Results from this study support the observations of others that HCC is on the rise in the United States 
. Our primary finding is that, among the three Latino populations compared, the incidence of HCC was highest among Latinos in South Texas. Between 1995 and 2006, age-specific HCC incidence rates increased from 40 to 79 years, and these increases were greater among Texas and South Texas Latinos than among those from SEER areas. The greatest APC in the incidence of HCC between 1995 and 2006 occurred among Latinos between 50 to 59 years of age.
The comparison of probable HCC risk factors shows that there was an increase in obesity among all three populations of Latinos and that obesity was highest among South Texas Latinos. We also found an increase in diabetes prevalence among U.S. Latinos and non-significant increases in diabetes prevalence among Texas and South Texas Latinos. Further, Latino women in South Texas had significantly higher diabetes prevalence than U.S. Latino women. We found no significant changes in heavy alcohol use among any Latino group, and only U.S. Latinos showed decline in the prevalence of cigarette smoking. Cigarette smoking and heavy alcohol use were similar among the three Latino groups.
Increasing diabetes and obesity prevalence may be relevant to the development of HCC in South Texas Latinos. The prevalence of these risk factors is higher in South Texas Latinos, so the attributable risk of HCC due to diabetes and obesity may be greater. The CDC reports that Latino adults 18 years of age and older are 1.2 times more likely to be obese than NLW, and among children aged 6–17 years of age Latinos are 1.4 times more likely to be obese than NLW 
, indicating an upward trend that may impact differential rates of obesity-related diseases including HCC. A recent study reported a 2-fold increased HCC risk in obese subjects, a 4-fold increased risk in diabetics and a 5-fold increased risk for obese diabetics, after adjustment for other known risk factors including infection with hepatitis B and C viruses 
. Although the study's sample size was modest, 37% of HCC cases without HBV and/or HCV infections were attributed to diabetes and obesity combined.
We speculate that Texas Latinos experience more obesity, diabetes and HCC than other Latinos because of cultural history, socioeconomic factors and maybe genetic predisposition. The composition of the Latino subgroups in Texas and SEER regions may differ, and their cultural traditions and immigration status may modify or impact the risk of cancer 
. In the U.S. overall, about 64% of Latinos are of Mexican origin; however, in Texas and South Texas, nearly 85% of Latinos are of Mexican origin 
. During the 20th
century, regional policies promising better housing, food and jobs attracted Mexican immigrants to South Texas where they subsequently adopted a more sedentary lifestyle and an Americanized diet that consisted of more fat and simple carbohydrates, less complex carbohydrates and less nutrient-dense vegetables and fruits 
. Additionally, about a third of the Mexican American gene pool is derived from Native American sources 
and since the latter may have a genetic predisposition to attributable risks for HCC 
, Mexican Americans could share this, and with it the likelihood of elevated rates of diabetes, obesity and alcohol use 
. We have evidence for example, that the so-called “reward" genotypes D2 dopamine receptor Taq 1A genotypes (A1A1, A1A2) have been associated with obesity, diabetes, alcohol and tobacco use as well as a variety of other problems 
A limitation of this study is that we do not have incidence data for hepatitis infection. HCC has long been associated with the hepatitis B and C viruses, focusing HCC etiology research on them and forecasting upward trends in HCC 
. A study of the prevalence of chronic HCV infection in Texas from 1988–1994 reported that 1.8% of all Texans were infected with HCV, 1.4% among whites and 2.0% among Latinos 
. Hepatitis infection is likely a strong risk factor for development of a proportion of Latino HCC cases; however, these attributable risks cannot alone explain the rising trends in HCC nor the differences in HCC incidence among the Latino groups compared in our study. Thus, productive avenues of HCC research should target not only hepatitis prevention, but also other preventable risk factors such as diabetes, obesity and heavy alcohol consumption.
To our knowledge, this is the first study to show increasing incidence of HCC in South Texas as well as increasing HCC risk factors among Latinos in this area. Given that 20% of U.S. Latinos reside in Texas, two-thirds of the population of South Texas is Latino (mainly of Mexican origin), and half of the HCC incident cases in Texas occur in South Texas, we have prioritized risks for HCC that may result in higher rates of the disease in this group, particularly diabetes and obesity. Although Latinos in Texas are no more likely than others to engage in excessive alcohol use or cigarette smoking, these behaviors remain as important risk factors for HCC. However, prevention efforts for Latinos in Texas should concentrate on addressing diabetes and obesity.
Most importantly, the risks we have identified are amenable to intervention. Clearly there is a need to focus on HCC prevention research and intervention which takes into account not only risks for the disease, but also genetic, cultural and socioeconomic predisposing features that may mediate the exposure-disease relationship. By understanding the components of cultural adaptation which influence health and disease, modifiable factors can be identified, populations at high risk can be targeted, and interventions can be tailored to fit the specific components affecting risk. Future studies using multifocal research and subsequent culturally sensitive intervention design, should target diabetes, obesity and other known factors related to liver cancer.
In summary, this study documents that the incidence of HCC among Latinos in South Texas is significantly higher than elsewhere in the United States. Higher rates of HCC among Texas and South Texas Latinos are likely the result of increased risks such as obesity and diabetes. Each of these has been shown to be a significant attributable risk for HCC among Latinos, and may be a consequence of cultural characteristics of this population. This indicates a need for further research to inform tailored prevention efforts directed at these risks among Latinos.