Obesity in Asian & Pacific Islander Americans: Research Priorities and Directions

1. Obesity in Asian & Pacific Islander Americans:Research Priorities and Directions May C. Wang, DrPH UCLA School of Public Health APIOPA Quarterly Meeting, Los Angeles, May 20, 2010

2. Overweight/Obesity is a risk factor for diabetes, cardiovascular disease, cancer and other chronic health conditions. • Among children, obesity is associated with poorer school performance, bullying, and lower self-esteem.

3. Question frequently asked, “What is the prevalence of obesity in the API population?” Rephrase to, “What are the prevalences of obesity in the API population?”

4. Best data on obesity rates for the nation comes from the NHANES (N ~ 5,000 per year) • NHANES does not yet have a representative sample of APIs • In 2007-2010, only 100 APIs were sampled. • For the 2011-2014 Cycle, the sample size for APIs will increase to 750 per year, giving a sample of 1500 for the 2011-2012 data cycle. Source: http://www.cdc.gov/nchs/nhanes/about_nhanes.htm

5. In California, we have CHIS… Report can be found at the UCLA Center for Health Policy Research website: http://www.healthpolicy.ucla.edu/pubs/Publication.aspx?pubID=329

6. Overweight and obesity rates are highest among NHPI & Filipinos From: Ponce, Tseng, Ong, et al. (2010). The State of Asian American, Native Hawaiian and Pacific Islander Health in California Report.

7. From: Ponce, Tseng, Ong, et al. (2010). The State of Asian American, Native Hawaiian and Pacific Islander Health in California Report. Similar pattern among children with Samoan children having very high rates of body composition not in the healthy fitness zone

8. But note! Data may have limitations.. • Adult data from CHIS and BMI is based on self reports of height and weight. • Child data from the CDE’s Fitnessgram program – reliability and validity of data have not been reported. • Still, subgroup patterns are probably accurate.

9. What about rates of chronic diseases among APIs?

10. Leading causes of death

11. In California in 2004… • Cancer is the leading cause of death among Chinese, Korean, and Vietnamese Americans. • Heart disease is the leading cause of death among Filipino, Japanese, Indian and NHPI Americans • Diabetes is of particular concern among Filipino, NHPI, Japanese, Chinese and Indian Americans.

12. Increasing and high rates of diabetes in Asians & Pacific Islanders Source: Offuce of Minority Health, USDHHS at http://minorityhealth.hhs.gov/templates/content.aspx?ID=3057

13. Obesity is a major risk factor for chronic diseases. • It is due to energy imbalance and can be attributable directly to diet and physical activity (chronic stress?) • Obesity rates are increasing. • Important to address obesity using a public health/preventive approach.

14. How to screen for obesity? Body Mass Index (BMI) or Quetelet Index Weight in kg/(Height in m)2

15. Current overweight/obesity cut-points recommended by CDC & WHO CDC: http://www.cdc.gov/obesity/defining.html WHO: http://www.who.int/mediacentre/factsheets/fs311/en/index.html

16. Are these cut-points appropriate for Asian populations? • Asians have higher % body fat but lower BMI than Whites (Wang, J, et al., 1994) • Lowest all-cause mortality associated with BMI 23.0-24.9 kg/m2 (Gu, 2006; Jee, 2006; Tsugane, 2002) • Asians have higher risk for CVD at any given BMI level (Razak, 2005; Razak, 2007; Odegaard, 2009)

17. Are these cut-points appropriate for Pacific Islander populations? • Pacific Islanders have lower % body fat but higher BMI than Europeans (Rush, 2009) • In a study of over 933 New Zealanders, Asian Indian men and women (BMI of 24 and 26 kg/m2, respectively) had the same percentage of Body Fat as Europeans with a BMI of 30 kg/m2 or Pacific Islander men and women with BMI of 34 and 35 kg/m2, respectively, suggesting that PI are more muscular.

18. Distribution of body fat varies with race/ ethnicity • South Asians have more centralized body data at a given BMI level (McKeigue, 1991) • East Asians have longer relative sitting height • PIs have longer leg length

19. Reasons to have sensitive cut-points for defining overweight/obesity in Asians & PIs • Increasing obesity rates in the Asian-Pacific Region • Urban-rural differences • Ethnic differences • PIs have especially high rates of obesity • Socioeconomic differences •  obesity rates associated with rapidly increasing diabetes rates Source: Report by the Regional Office of WHO Western Pacific Region, IASO, and IOTF, 2000

20. Lower (Asians) and higher (PIs) cut-points recommended

21. Are different cut-points for defining overweight and obesity recommended for Asian and Pacific Islanders Americans?

22. What are the consequences of using global cut-points? • For Asian Americans, it means that a higher percentage of overweight and obese individuals will not be screened positive (overweight/obese), and therefore not referred for treatment. • For Pacific Islander Americans, it means that a higher percentage of ‘healthy’ weight individuals will be screened positive (overweight/obese) and therefore unnecessarily referred for treatment.

23. Are the WHO recommended cut-points appropriate for Asian and PI Americans? Questions: • Are API Americans at a different risk for obesity-related conditions at a given BMI? • Are there differences in these relationships between APIs raised in API societies and APIs raised in western societies?

24. Few studies • Most of Asian Americans, not of Pacific Islander Americans.

25. Are Asian Americans at a higher risk for obesity-related conditions at a given BMI? • Several studies of Asian immigrants suggest higher levels of CVD risk factors at a given BMI. • For example, in a random sample of 1078 Canadians including Chinese and South Asians, higher levels of glucose and lipid-related factors. (Razak, 2007)

26. Wang, Jack, et al. Am J Clin Nutrition, 1994 N = 242 Asian (97% born in Asia) and 445 White adults (18-94 yr) Results: • Asians have more % body fat than Whites at the same level of BMI • Asians had more subcutaneous fat in the arm and trunk

27. Do young adult Asian Americans born in America have an excess of adipose tissue at a given BMI? Used anthropometric and body composition data from Berkeley Bone Health Study (1998-2000) N=690 Non-Hispanic Black and White women aged 20-24 years Latina & Asian Bone Health Study (1998-2000) N=291 Latinas and Asian women aged 20-25 years

28. Do young adult Asians have an ‘excess’ of adipose tissue at a given BMI? • Height and weight were measured • Body composition (fat mass and lean mass) measured using DXA (Lunar IPX-IQ) • Compared mean % body fat among US-born Asians, foreign-born Asians and non-Hispanic Caucasians at varying levels of BMI • Examined association between BMI and % body fat using linear regression

29. Description of Sample Asians (N=132) • Age = 22.0  1.0 • 47% US born, 53% foreign-born • 50% Chinese, 14% Korean, 7% Filipino, 5% Japanese, 5% Other Caucasians (N=279) • Age = 21.9  0.9

30. At varying BMI levels, US-born Asian young women have lower % BF than foreign-born Asian and Caucasian American women 7 8 79 10 11 48 42 41 139 61 59 279 42 39 121

31. Preliminary finding • Some preliminary evidence in young adults suggesting that US-born Asian Americans have lower adiposity than foreign-born Asian Americans at the same BMI level.

32. Implications for practice • BMI is simply a tool for screening for individuals who may be at risk for obesity-related chronic diseases • No evidence to indicate a need for lowering cut-points for young Asian American women raised in North America • APIs are a heterogeneous group • Helpful for clinicians to understand that each sub-group may different risk factors for chronic diseases – whether raised in the United States, South Asian vs. East Asian, PIs vs. Asians, etc.

33. Research priorities & directions • Adiposity increases over the life course • Do US-born APIs increase % body fat at a different rate than foreign-born APIs? • Is the distribution of body fat for APIs raised in API societies different than that for APIs raised in North America? • What are effective intervention strategies for addressing obesity? • What other factors influence Asian & Pacific Islander Americans’ risk for diabetes and other chronic diseases?

34. Thank you!Gracias!Arigato! Xie Xie! Tu Ji Shay!Salamat! Contact Information: May Wang, DrPH UCLA School of Public Health Email: maywang@ucla.edu