CAUSES: Causes of Asian American Mortality Understood by Socioeconomic Status

Dr. Latha Palaniappan

Using local, state, and national death/mortality datasets, investigators from Stanford University are examining racial/ethnic, nativity, and geographic differences in Asian American subgroup mortality compared to other racial/ethnic groups. In this interview, Co-Principal Investigator Dr. Latha Palaniappan, a clinical professor at the Stanford University School of Medicine in Palo Alto, California, describes CAUSES: Causes of Asian American Mortality Understood by Socioeconomic Status, a NIMHD-funded RO1 grant.

What was the impetus for this research study?

As the fastest racial/ethnic and now immigrant group in the United States, Asian Americans have been largely understudied. Our current understanding of Asian American health is based on an aggregated group, yet we know that Asians are an incredibly diverse population. The six largest subgroups are Asian Indians, Chinese, Filipino, Japanese, Korean, and Vietnamese, which constitute approximately 86 percent of all Asian Americans, and each has a wide range of disease risks, immigration histories, and socioeconomic status. Our study aims to highlight heterogeneity in mortality outcomes to lead the discussion on the importance to disaggregate these populations in national health databases.

Can you describe the research that you are conducting?

The Causes of Asian American Mortality Understood by Socioeconomic Status (CAUSES) Study has three specific aims:

  • To determine the leading causes of death between the six largest Asian subgroups
  • To evaluate whether nativity (foreign-born vs. U.S.-born) influences cause-specific mortality and survival within each Asian American subgroup
  • To test whether county-level social, economic, health services, environmental, and demographic factors explain mortality and survival differences between Asian American subgroups compared with non-Hispanic Whites

What findings from your data can you share?

So far, we have published two papers based on our findings. Our first paper looked at cause-specific cardiovascular mortality between the six diverse Asian subgroups. Most notably, we found that Asian Indians and Filipinos proportionally die more due to heart disease than any other Asian subgroup and non-Hispanic White counterparts. This study also showed that Asian Indians and Filipino men especially die at younger ages than other Asian subgroups and non-Hispanic Whites, so early targeted and preventive medicine is critical for these Asian subgroups.

Our second paper reported the top causes of death among the six largest Asian subgroups, aggregate Asians (combined six groups), and non-Hispanic Whites. We demonstrated the heterogeneity in the leading causes of deaths and mortality disparities that are masked when only reporting data by aggregated Asian Americans. Large national databases continue to collect data by a single Asian group, but our study demonstrates that doing this misses important information. Notably, we found that, when aggregated, the top cause of death among Asian Americans is cancer. However, when disaggregated, there is wide variation in the leading cause of death. For instance, for Asian Indians, nearly twice as many men die of heart disease (31 percent), compared to cancer (18 percent). In contrast, for Koreans, the opposite is true — the death rate for cancer (34 percent) is much higher than the death rate for heart disease (19 percent).

What is significant about these findings in terms of health disparities research?

This is the first time that research on a national scale has looked at mortality data for the six largest Asian American subgroups. It was not until recently (2003) that the death records created a new standard to collect data by disaggregated Asian subgroups (Asian Indians, Chinese, Japanese, Koreans, and Vietnamese). In doing so, we were able to capture important disparities for certain Asian subgroups that often go masked when traditional national surveys collect and report data for aggregated Asian Americans. We have previously shown this for cardiovascular risk factor data as well using electronic medical records in the Bay Area in California.

Have you found anything surprising or unexpected from your research?

Given the diversity in lifestyles, dietary patterns, and cultures across Asian subpopulations, I don’t think it’s too surprising to see the heterogeneity in mortality outcomes between groups. It is more surprising that this type of study hasn’t been done earlier. This study enables us to provide an empirical basis for the importance of disaggregation in future national databases in order to fully capture health disparities among Asian populations.

What are the next stages for this study?

There are many projects we are working on that seek to disentangle the ambiguities in mortality outcomes between the different Asian groups. One of our aims is to link county-level socioeconomic information to mortality to begin describing why we may see these disparities between subgroups. Additionally, we are now working to disaggregate Hispanic/Latino subgroups to highlight the potential differences among these diverse populations as well.

How can this research help improve minority health and/or the reduction/elimination of health disparities?

Our take-home message is always to stress the importance of disaggregation when reporting health information on diverse racial groups. Asian Americans and Hispanic/Latinos, for example, have very diverse ethnic groups, that often demonstrate differential lifestyles, genetics and cultures that often play a role in health outcomes. Identifying these disparities allows researchers, clinicians, and policymakers to reevaluate current data collection mechanisms and to have better targeted preventative medicine and outreach efforts.

For more information, contact Dr. Irene Dankwa-Mullan.