Presented to Pulse of AsiaDaegu, Korea

April 17, 2009

By

Ted Greiner, Professor of NutritionDept of Human Ecology, Hanyang University

Seoul, Korea

Not enough!The amount of research that has been

done appears to me inadequate to answer many of the questions we might want to ask

I will review a few of what seem to be to be fairly clear findings and hypotheses

I will also present some findings, both from the literature and from my own students’ work (Chinese and Mongolians studying in Sweden) that often seem to raise as many questions as they answer

Do immigrants copy behavior of the host population?Kockturk, who studied breastfeeding among

immigrants to Sweden did not think soShe hypothesized that they copy what they

assume is the behavior of rich people in their home country

But a later study of Bangladeshi immigrants to Sweden Rehana suggested that the truth may often lie somewhere in between: they breastfed longer than Swedes but more exclusively than Bangladeshis in the early months

It is unclear whether:1. Ethnic group variation occurs in

acculturation-health relationships2. Acculturation components vary

differently in relationship to health3. Biculturalism has beneficial effects

on health**Quoted from Lee et al. Acculturation and health in Korean

Americans. Social Science & Medicine 2000;51: 159-173.

Chinese ethnic immigrants have better heart health

Ethnic Chinese immigrants to Canada had lower age-standardized death rates from cardiovascular and ischemic heart disease and congestive heart failure for both genders

All these rates were higher in Canadians, South Asian immigrants and other immigrants (and similar to each other)*

*Sheth T, et al. Cardiovascular and cancer mortality among Canadians of European, south Asian and Chinese origin from 1979 to 1993: an analysis of 1.2 million deaths. JAMC 1999;161(2):132-138

Chinese ethnic immigrants have better heart health

Thus there was little if any “healthy migrant” effect.

Death rates were not lower in Chinese for cerebrovascular disease.

Findings were similar to those from USA and China

The Chinese had low serum cholesterol levels (4.1 mmol/L)

Why is immigrant health better?The standard hypothesis is that immigrants

enjoy better heart health mainly for the first generation.

As they adopt the lifestyle of their new country, their patterns of health change to become like that of the host country.*

Major factors that would confound this include intergenerational maintenance of home-country dietary patterns and genetic factors.

*Time travel with Oliver Twist--towards an explanation for a paradoxically low mortality among recent immigrants. Razum O, Twardella D. Trop Med Int Health. 2002 Jan;7(1):4-10.

Does East Asian immigrant heart health worsen in the West?The incidence of myocardial infarction was half

that in Japanese in Japan than in Hawaii and 50% greater in California (CA) than in Hawaii.*

Among Chinese in CA, cholesterol was no higher in those born in CA, than those born in China, but BMI and hypertension in men were higher; smoking was lower in men but higher in women.**

*Robertson TL et al. Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California. Incidence of myocardial infarction and death from coronary heart disease.Am J Cardiol. 1977;39(2):239-43.**Klatsky AL, Armstrong MA. Cardiovascular risk factors among Asian Americans living in northern California. Am J Publ Health. 1991;81(11):1423-8.

Mechanisms of changeHigh consumption of fish, soy, seaweed and

vegetables may protect heart health and may explain why Okinawans are better off than other Japanese, both at home and abroad.*

Chinese in N America ate more fruit and vegetables when living with older Chinese--who strongly prefer Chinese food. Younger, working Chinese felt there was no difference in how healthy Chinese diets are and found them inconvenient to prepare.**

*Yamori Y et al. Implications from and for food cultures for cardiovascular diseases: Japanese food, particularly Okinawan diets. Asia Pac J Clin Nutr. 2001;10(2):144-5.**Satia-Abouta J et al. Psychosocial Predictors of Diet and Acculturation in Chinese American and Chinese Canadian Women. Ethnicity and Health 2002;7(1):21-39.

How about emigrants TO East Asia? I only found one relevant study, which compared local ethnic

Chinese in Singapore with local South Asians (SA) and Malays (M)

Chinese had lower death rates (age 30-69) for ischemic heart disease and hypertensive disease (for each sex) but not cerebrovascular disease*

The Chinese had the lowest prevalence of diabetes and the lowest rate of cigarette smoking

Malays had higher blood pressure South Asians had lower high density lipoproteins**

*Hughes K, et al. Cardiovascular diseases in Chinese, Malays, and Indians in Singapore. I. Differences in mortality. J Epidem Comm Health. 1990;44(1):24-8.**Hughes K, et al. II. Differences in risk factor levels. J Epidem Comm Health. 1990;44(1):29-35.

Koreans who moved to the USABased on careful theoretical work and

examining degree of acculturation better than most have done, Lee et al* studied Koreans who moved to the USA

Regarding the impact of immigration on health, very few clear relationships emerged. (Most observed relationships seemed quite complex.)

*Lee et al. Acculturation and health in Korean Americans. Social Science & Medicine 2000;51: 159-173.

Koreans who moved to the USAOnly about half got even light exercise regularly

27% of men and 9% of women were current smokers

The mean BMI was 24 for men and 21 for women

Fat intake was not related to acculturation

Koreans who moved to the USAThe more acculturated men were heavier but reported being more healthy

But we are uncertain of their definition of health

And Koreans have not been living in the USA for as long as other immigrant groups

Do ethnic East Asians respond differently to risk factors?Serum cholesterol is a risk factor in Chinese in

China, even when levels are quite low by Western standards*

The increased incidence of heart disease among Japanese living in Hawaii compared to Japan had the usual risk factor associations: systolic blood pressure, serum cholesterol, relative weight and age

Smoking was an exception (not a risk factor)** *Chen Z, et al. Serum cholesterol concentration and coronary heart disease in population with low cholesterol concentrations. BMJ. 1991;303(6797):276-82. **Robertson TL et al. Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California. Coronary heart disease risk factors in Japan and Hawaii. Am J Cardiol. 1977;39(2):244-9.

Complex genetics is sometimes involvedCanadian South Asian (SA) immigrant patients in rehab for coronary artery disease (and not taking B vitamins for one mo) had similar levels of plasma homocysteine (PH) to Canadians, but East Asian (EA) patients’ levels were lower (1/5 as many were abnormal (PH > 12 μmol/l)).*

*Senaratne et al. Possible Ethnic Differences in Plasma Homocysteine levels associated with coronary artery disease between South Asian and East Asian immigrants. Clin Cardiol 24,730-734 (2001).

Complex genetics is sometimes involvedLipid subfractions, diabetes and

hypertension levels were similarVegetable intake was higher in SA than

EA Thus PH differences could be genetic The relative contribution of PH in

relation to the pathogenesis of atherosclerosis in EA patients appears to be negligible

Unpublished masters theses asters theses from Uppsalafrom Uppsala

Su Hebate. Dietary acculturation of Chinese residents in Uppsala. Masters thesis, Uppsala University Department of Women's and Children's Health, 2003.

Chen Wen. Cardiovascular disease risk factors in Chinese residents in Uppsala, Sweden. Masters thesis, Uppsala University Department of Women's and Children's Health, 2004.

1. Dietary acculturation of Chinese residents in Uppsala76 Chinese residents in Uppsala, Sweden

were interviewed; data were complete on 68

Participants were identified by a modified “snowball” method beginning with a list provided by the Chinese Association in Uppsala

Born in China but lived in Sweden > 3 months; >18 years of age

They were asked only about how their diets changed – no other dietary assessment was conducted

Results The following foods were consumed more in Sweden than had been in China:cheese (72.1%)butter (64.7%)milk (54%)chicken/poultry (70.6%)fruit (57.4%) coffee (61.8%)potato (48.5 %)egg (47.1 %)

Results, cont The following foods were consumed

less in Sweden than had been in China:legumes and legume products (89.7%)animal fat (51.5%)fatty meat (52.9%)fish/shellfish (54.4%)dark green leaves vegetables (85.3%)other green leafy vegetables (66.2%)other vegetables (61.8%) snack food (66.2%)alcohol (48.5 %)

Factors IncreasedN %

Same N %

DecreasedN %

Concern about health

22 32.4

40 58.8

6 8.8

Concern about weight

10 14.7

48 70.6

10 14.7

Concern about price

38 55.9

21 30.9

9 13.2

Changes in Factors that influenced dietary habits after coming to Sweden

Determinants of Dietary Change Many statistical tests were performed,

so these results need to be interpreted with caution

Very few of the potential associations were statistically significant – only the significant ones are reported here

Women decreased lard consumption more than men (68 vs 35%)

People living with someone else increased consumption of poultry and fruit more than those living alone

Determinants of Dietary Change Those with higher incomes ate more

fruit and cheese but less legumes Those who had lived longer in Sweden

increased fruit consumption more Those who most increased their fruit

consumption were more likely to have gained weight after coming to Sweden

2. Cardiovascular disease risk factors in Chinese residents in SwedenBased on interviews with a sample of 80

individuals aged 18-64 yearsBorn in China but lived in Sweden > 3

monthsParticipants were identified by a

modified “snowball” method beginning with a list provided by the Chinese association in Uppsala

Height, weight and blood pressure were measured

Results 81.3% thought that cardiovascular

disease could be preventedRisk factors they listed (with no

prompting) were:Fat in food, 58.8% Lack of exercise, 47.5% Stress, 31.3%Smoking, 13.8%obesity, 7.5% diabetes, 2.5% Hypertension, 3.8%

Results contRisk factors they had:

Smoking, 10%, but none>10 cigarettes/day; another 7.5% quit after arriving in Sweden

Overweight, 11.3% (mean BMI 22.3±2.6)Obesity, 1.3%Hypertension, 13.8% (mean SBP and DBP

were 116.1±16.4mmHg and 74.9±10.9mmHg respectively)

Free-time physical inactivity, 52.5% Family history of CVD, 51.3% (37.5%

father; 43.8% mother)

Determinants Gender, age, education level, income level, living status and length of stay in Sweden were examined for links with risk factors

The findings are presented in the following slides

CV risk factors by genderGender Male Female n 40 40 %

Smoking 15 5overweight 15 7.5hypertension* 22.5 5Physical inactivity 52.5 52.5family history 47.5 55

mean±SDBMI** 23.2±2.5 21.4±2.5

SBP** 121.6±15.8 110.4±15.1 DBP** 79.0±11.0 70.8±9.2 Chi-square test for differences in proportions between groups. One-way ANOVA

was used to compare means difference between groups.* p<.05; ** p<.01

CV risk factors by age Age in years ≤34 35-44 ≥45 N 37 29

14 %Smoking 8.1 10.3

14.3 Overweight* 0 20.7

21.4 Hypertension* 5.4 13.8

35.7 Physical inactivity 59.5 48.3 42.9Family history 48.9 51.7

51.7 mean±SDBMI** 21.2±1.8 23.0±3.1

23.8±2.1SBP 114.1±12.0 113.6±13.1

126.3±27.0DBP* 72.2±8.7 75.1±11.0

81.5±13.7 Chi-square test for differences in proportions among groups. One-way

ANOVA was used to compare means difference among groups.* p<.05; ** p<.01

CV risk factors by length of stay in Sweden Months 3-12 13-60 61-120 >120 n 24 23 19 14 %

Smoking 4.2 8.7 15.8 14.3

Obesity 4.2 13.0 15.8 14.3 Hypertension 12.5 4.3 10.5 35.7 Physical inactivity ´ 41.7 47.8 78.9 42.9Family history 58.3 39.1 57.9 50 mean±SD

BMI 22.6±2.7 21.9±2.5 21.7±2.8 23.3±2.4

SBP 115.8±10.9 114.0±12.9 114.2±18.1 122.5±25.1 DBP 74.6±10.9 72.3±8.1 75.7±10.6 78.6±14.8 Chi-square test for differences in proportion among groups. One-way ANOVA was used to

compare means differences among groups.* p<.05; ** p<.01

Comparison of risk factors between hypertensives and non-hypertensives

Hypertension non-hypertension

N 11 69 mean±SD BMI** 25.0±3.4 21.9±2.2

%Overweight 27.3 8.7

Smoking:**

Never 36.4 89.9 Former 27.3 4.3Current 36.4 5.8 Chi-Square test or Fisher’s exact test for the frequencies difference

between groups. One-way ANOVA for means differences between groups. *P<0.05; **P<0.01.

Is moving to Sweden less harmful to East Asians than moving to USAThere appears to be some evidence for thisMoving to Sweden may have reduced intakes

of saturated fats and cholesterol, reduced smoking and heavy alcohol use, increased consumption of fruits (and whole grains), and increased physical exercise

But it may have reduced intake of vegetables, certain types of fish, soy, and seaweed

AND, the data are far too inadequate to say for certain!

Thank you!Full text copies of these two theses and

some published papers on obesity in China and Mexico can be downloaded at:

http://global-breastfeeding.org/category/obesity/

(Or go to www.global-breastfeeding.org and click on “obesity” on the right side)