The Mediterranean score of dietary habits in Chinese ... - Nature

European Journal of Clinical Nutrition (2001) 55, 215±220 ß 2001 Nature Publishing Group All rights reserved 0954±3007/01 $15.00 www.nature.com/ejcn

The Mediterranean score of dietary habits in Chinese populations in four different geographical areas J Woo1*, KS Woo1, SSF Leung1, P Chook1, B Liu1, R Ip1, SC Ho2, SW Chan3, JZ Feng4 and DS Celermajer5 1

Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, People's Republic of China; 2Department of Community and Family Medicine, The Chinese University of Hong Kong, Hong Kong, People's Republic of China; 3Chinese Hospital, San Francisco, California, USA; 4Guangdong Provincial Cardiovascular Institute, Guangzhou, People's Republic of China; and 5 Department of Cardiology, The Royal Prince Alfred Hospital, Sydney, Australia

Objective: To compare the dietary intake of Chinese people living in Pan Yu, Hong Kong, San Francisco and Sydney with respect to cardiovascular health, using the Mediterranean diet score, examining the effects of age, gender, urbanization and acculturation on the diet score. Subjects: A total of 500 men and 510 women in Hong Kong were recruited as a territory-wide strati®ed random sample. Subjects were recruited in response to local advertisements for the other three sites: Pan Yu, 58 men, 95 women; San Francisco, 166 men, 192 women; Sydney, 95 men, 73 women. Method: Food-frequency questionnaire over a 7 week period. A high=healthy score was taken as 4 for men and 3 for women, representing a dietary pattern bene®cial for cardiovascular health. Results: In Hong Kong, more women in the middle age group (35 ± 54) had a high score than other age groups, and overall more women had high scores than men. In comparing the four geographical regions, Pan Yu had the highest number of subjects with high score, and Hong Kong had the lowest. With the exception of the younger population and men in Hong Kong, the percentage of the population with a high score in all sites is greater than among elderly Greeks consuming a more traditional heart-healthy Mediterranean diet. Conclusion: Considerable variations in Chinese dietary patterns exist with respect to age, gender and geographic location. Overall, the Chinese diet is comparable to the Mediterranean diet and may be expected to have similar health bene®ts that have been documented for the traditional Mediterranean diet. Descriptors: Chinese diet; cardiovascular disease; acculturation; urbanization; Mediterranean diet European Journal of Clinical Nutrition (2001) 55, 215±220

Introduction The dietary pattern of inhabitants around the shores of the Mediterranean has long been noted to have health bene®ts, particularly with respect to coronary heart disease (Keys, 1995; Nestle, 1995). The main features of the diet are: high consumption of fruits, vegetables, legumes and grains; foods with high monosaturated to saturated fats ratio; moderate consumption of dairy products and ethanol (mainly wine); and low consumption of meat and meat products (Trichopoulou & Lagiou, 1997). Longitudinal studies and randomized controlled trials showed that a Mediterranean dietary pattern is associated with improved survival among elderly Europeans (de Groot et al, 1996; Osler & Schroll 1997), possibly reduced cancer rate (de *Correspondence: J Woo, Department of Medicine and Therapeutics, Prince of Wales Hospital, Shatin, NT, Hong Kong SAR, People's Republic of China. E-mail: [email protected] Received 6 September 2000; revised 3 November 2000; accepted 6 November 2000

Lorgeril et al, 1998), and reduced cardiovascular complications after myocardial infarction (de Lorgeril et al, 1999). The diet emphasizes food groups rather than speci®c nutrients, and this traditional plant-based diet may provide bene®t through the intake of antioxidants, ®bre, or indirectly by lowering blood pressure (de Lorgeril, 1998). While individual items of the Mediterranean diet may not be predictive of outcome, the extent to which dietary patterns conform to the Mediterranean diet, quanti®ed as a score, is predictive of outcome (de Groot et al, 1996; Osler & Schroll 1997). Among Chinese populations, the incidence of coronary heart disease is lower than in Caucasians (Woo & Donnan, 1989), and a difference in dietary habits may be a contributory factor. The Chinese diet has many similar features with the Mediterranean diet, in that vegetable and fruit consumption is high, and fat and meat consumption is low. However, there is no longitudinal observation study or randomized controlled trial to determine if a traditional Chinese diet is related to improved survival or better health outcomes. Since such evidence is available for the Mediterranean diet, it would be of interest to determine

Mediterranean score in Chinese J Woo et al

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whether the dietary habit of Chinese populations is similar, by quantifying the features using the Mediterranean diet score, developed by other researchers (de Groot et al, 1996). The proportion of the population with a high score representing a dietary pattern bene®cial to cardiovascular health may be compared with published studies for Caucasian populations, as a useful indicator of the dietary pattern of the community with respect to chronic diseases. In this study, the Mediterranean score is calculated for Chinese populations in four geographic regions throughout the world, and the effect of age, gender, urbanization, acculturation and, indirectly, the effect of public health education in different countries on the Mediterranean score is also examined.

Subjects and method Four cohorts of ethnic Chinese subjects living in Hong Kong, a rural village on the outskirts of Pan Yu in Guangdong province in Southern China, in Sydney and in San Francisco were studied. (Hong Kong), 500 M, 510 F; Pan Yu, 58 M, 95 F; San Francisco, 166 M, 192 F; Sydney, 95 M, 73 F). Subjects in the Hong Kong cohort were recruited as part of a territory-wide cardiovascular risk factor study from October 1995 to May 1996, a strati®ed random survey where the sample was representative of the Hong Kong population. Details of the recruitment have been given elsewhere (Woo et al, 1998). The other three cohorts were community volunteers. The total population of the rural village, Pan Yu district, China, is approximately 3000, and has one of the lowest annual rates of acute myocardial infarction in this region, being approximately 40 per 100 000 among those age 40 y and over, compared with 90.8 ± 117.3 per 100 000 in Hong Kong (Woo & Donnan, 1989). Posters advertising a cardiovascular risk factor survey were placed in the community in the vicinity of the hospital or health centre. All advertising material was written only in the local language in each centre. For San Francisco and Sydney, subjects were included if they were originally of southern Chinese origin (for the past three generations), and had lived in these cities for at least 10 y. Dietary intake was assessed in all cohorts using the same food frequency method. The quantity and frequency of consumption per day and per week for each item were recorded with the aid of photographs to illustrate portion sizes, and nutrient quantity was calculated using food tables from multiple sources Ð UK and two mainland Chinese institutions. Details of the method have been described elsewhere (Woo et al, 1997). The Mediterranean score was calculated according to the consumption of eight categories of food, and a score of one was given if the criteria for each category was full®lled (de Groot et al, 1996): 1. High monounsaturated: saturated fat ratio (> 1.6). 2. Moderate ethanol consumption (men: < 10 g=day). European Journal of Clinical Nutrition

3. High consumption of legumes (men > 60 g=day, women > 49 g=day). 4. High consumption of cereals (mean > 291 g=day, women > 248 g=day). 5. High consumption of fruits (men > 249 g=day, women > 216 g=day). 6. High consumption of vegetables (men > 303 g=day, women > 248 g=day). 7. Low consumption of meat and meat products (men < 109 g=day, women < 91 g=day). 8. Low consumption of milk and dairy products (men < 201 g=day, women < 194 g=day). These values were adjusted to daily intakes of 2500 kcal for men and 2000 kcal for women. For our population, since very few women drink, item 2 was deleted, so that a total score of 7 for women was used instead of 8. For this study, a high score for men is de®ned as 4 for men, and 3 for women, and represents a dietary pattern that is bene®cial for cardiovascular health. A score of 3 or 4 has also been used to relate Mediterranean dietary pattern to better health outcomes (Osler & Schroll, 1997). Mean nutrient intakes between the four cohorts were compared using Tukey's method of pairwise multiple comparisons. Chi-square test was used to compare the number of subjects with high score between different age and sex groups, and between different geographical regions. Results The mean nutrient intake of Chinese people in the four regions is shown by age and sex in Table 1. For the younger age group (34 y), there was no difference in energy intake among men, but women in San Francisco had the lowest intake. Men and women in Pan Yu had the highest carbohydrate and lowest protein percentage of total energy compared to the other regions. Men in Pan Yu also consumed the lowest percentage fat. The MUFA:SFA ratio was also the highest for both men and women in Pan Yu, while the PUFA:SFA ratio was also the highest among men in Pan Yu. Both men and women in Hong Kong had the highest cholesterol intake per 1000 kcal of energy compared with other regions, while women in Hong Kong also had the highest percentage fat consumption. Among middle aged Chinese (35 ± 54 y), men in Sydney and Hong Kong had higher energy intakes. The lowest percentage protein was still observed for the Pan Yu population, while it was highest for San Francisco. Interestingly, the percentage fat was highest for Pan Yu; at the same time the MUFA:SFA and PUFA:SFA ratio were also high. The cholesterol intake was also the highest in Hong Kong, as for the younger age group. For the older age group (55 y), fewer differences between regions were observed. The pattern of lowest protein percentage, higher fat percentage and MUFA:SFA ratios in the Pan Yu population was also observed.


217 Table 1 Mean (s.d.) nutrient intake in four regions by age and sex Male Macronutrient composition (A) 34-y-old or below n Energy (kcal) Carbohydrate (%) Protein (%) Fat (%) MUFA:SFA PUFA:SFA Cholesterol (mg=1000 kcal) (B) 35 ± 54-y-old n Energy (kcal) Carbohydrate (%) Protein (%) Fat (%) MUFA:SFA PUFA:SFA Cholesterol (mg=1000 kcal) (C) 55-y-old or above n Energy (kcal) Carbohydrate (%) Protein (%) Fat (%) MUFA:SFA PUFA:SFA Cholesterol (mg=1000 kcal)

Female

Sydney

Pan Yu

San Francisco

Hong Kong

Sydney

Pan Yu

San Francisco

Hong Kong

11 2622 (736) 51a (10) 18 (4) 31 (8) 1.26a (0.21) 0.87 (0.23) 137.80 (57.6)

21 2596 (879) 60a*b (12) 15b (4) 25b (12) 1.62a***b (0.38) 1.01b (0.48) 117.00b (68.2)

28 2173 (749) 49b*** (9) 21b*** (7) 30 (8) 1.26b*** (0.28) 0.73b** (0.35) 145.6 (53.8)

103 2557 (723) 52b** (7) 19b*** (3) 30b* (6) 1.27b*** (0.01) 0.77b** (0.21) 170.2b*** (45.6)

11 1931 (766) 55 (12) 16a (6) 25a (8) 1.15a (0.18) 0.86 (0.44) 88.60a (39.4)

45 1982b (649) 59b (10) 15b (4) 26b (9) 1.48a***b (0.30) 0.85 (0.45) 134.3b (61.5)

28 1502b**c (592) 53 (12) 20b*** (6) 27c (9) 1.27b*** (0.21) 0.79 (0.42) 150.1a* (78.7)

106 1891c* (583) 50b*** (7) 20a*b*** (3) 32a**b***c* (5) 1.27b*** (0.13) 0.84 (0.24) 171.5a***b*** (47.8)

67 2556a (1051) 55 (8) 19a (5) 26a (6) 1.35a (0.20) 1.01a (0.40) 109.80a (47.1)

19 2147 (499) 54 (12) 16a*b (4) 30a*b (11) 1.56a***b (0.30) 1.11b (0.65) 162.6a***b (71.6)

91 2200a*c (810) 52 (9) a 23 ***b***c (6) 25b*c (8) 1.41b*c (0.35) 0.89b* (0.34) 124.8b*c (56.6)

267 2470c*** (650) 53 (8) 19c*** (3) 29a***c*** (6) 1.29b***c*** (0.12) 0.81a***b*** (0.24) 171.0a***c*** (53.90)

48 2061 (1160) 53 (8) 19a (4) 30 (8) 1.41a (0.34) 1.10a (0.39) 110.00a (48.2)

29 2113 (668) 55 (10) a 14 ***b (5) 32b (10) 1.70a***b (0.30) 1.22b (0.62) 125.8b (70.1)

110 1759 (676) 52 (8) a 21 ***b***c (6) 28b* (7) 1.38b***c (0.36) 0.95b** (0.40) 132.4c (54.60)

276 1857 (598) 53 (7) b 19 ***c*** (3) 29 (5) a b 1.29 * ***c** (0.16) 0.94a*b*** (0.31) 154.9a***b*c** (54.1)

17 2336 (749) 53 (6) 20a (4) 28 (7) 1.36a (0.23) 0.99 (0.32) 118.9 (38.3)

18 2379 (686) 52 (10) 15a*b (5) 29b (8) 1.67a***b (0.22) 0.94 (0.29) 141.8 (71.0)

47 1966 (817) 55 (9) 21b***c (7) 24b**c (6) 1.42b***c (0.29) 1.13c (0.45) 122.8 (63.5)

130 2211 (612) 57 (8) 18c*** (3) 27c* (7) 1.31b***c** (0.14) 0.91c*** (0.30) 137.8 (55.7)

14 1948 (834) 57 (10) 19 (4) 25 (7) 1.42 (0.17) 1.01 (0.41) 118.9 (53.2)

21 1827 (589) 58 (9) 15b (3) 28 (9) 1.61b (0.27) 1.04 (0.41) 123.6 (47.0)

54 1657 (928) 54 (9) 22b***c (7) 25 (9) 1.41b* (0.44) 0.98 (0.46) 132 (60.1)

128 1654 (454) 57 (7) 18b*c*** (3) 27 (5) 1.31b*** (0.17) 0.96 (0.35) 136.7 (48.4)

a

Differ signi®cantly from Sydney. Differ signi®cantly from Pan Yu. c Differ signi®cantly from San Francisco. *P < 0.05; **P < 0.01; ***P < 0.001. Post hoc pairwise multiple comparisons (Tukey method). b

The Mediterranean score was calculated for men and women, and the number of subjects divided into those with low and high scores. The score differed by age and gender among the Hong Kong population only (Table 2). More

women in the middle age group (35 ± 54) had a higher score compared with other age groups, while more men had lower scores than women. The number of men and women with high scores was the highest in Pan Yu and European Journal of Clinical Nutrition


218 Table 2 Mediterranean score of the Hong Kong population by age and gender

Chinese dietary patterns with age, gender, and geographical locations.

Mediterranean score high scorea Sex and age group Female age 34 or below Female age 35 ± 54 Female age 55 or above Male age 34 or below Male age 35 ± 54 Male age 55 or above

n

Count

%

Discussion

106 276 128 103 267 130

66 209 85 42 129 81

62 76 66 41 48 62

To date, the only studies relating dietary patterns to health outcomes are those relating to the Mediterranean diet (Keys, 1995; Nestle, 1995; Trichopoulou & Lagiou, 1997; de Groot et al, 1996; Osler & Schroll, 1997; de Lorgeril et al, 1998; de Lorgeril, 1998). These studies suggest that dietary habits may be considered as a risk factor for cardiovascular diseases or survival in older populations. It is likely that the lower incidence of cardiovascular diseases in Chinese populations may be partly attributed to the Chinese diet. Although there are many variants of the Mediterranean and Chinese diets, the development of a Mediterranean diet score in some previous studies (de Groot et al, 1996; Osler & Schroll, 1997) enables a quantitative comparison of the Chinese and Mediterranean dietary habits. There are limitations in using a dietary score devised by another author, in that the characteristics of the population to which the score applies will be different to Chinese populations. Furthermore, there may be other characteristics in the Chinese diet with adverse or bene®cial effects to health that have not been taken into account in comparison with different populations. The percentage of the population with a high score ranges from 51% to 96% in four geographic regions with different culture, educational background and socioeconomic characteristics. With the exception of the younger population and men in Hong Kong, the percentage with a high score was greater than the percentage among elderly Greeks (57%) (Trichopoulou et al, 1995). Therefore Chinese populations as a whole have a dietary pattern similar to the Mediterranean dietary pattern, the majority achieving a high score irrespective of acculturation, age or socioeconomic factors. It is possible that the current dietary patterns of Chinese populations may be `healthier' with respect to cardiovascular disease compared with the `Mediterranean' population, since the Mediterranean diet is a traditional diet and studies suggest that there has been a deviation from traditional dietary patterns with time (FerroLuzzi & Branca, 1995; Alberti-Fidanza et al, 1999). Among the Chinese population, the dietary pattern shows interesting variations with age, gender and geographical region, re¯ecting in¯uences of local culture, health messages promulgated by media and the government, differences in education, economic status and degree of urbanization. In Pan Yu, being a rural area, the population will tend to preserve a more traditional dietary pattern, and their relatively lower income may preclude a diet high in protein from meat or seafood. However, they will be less exposed to nutrition education compared with societies in San Francisco or Sydney, and this may be re¯ected in the observation that the percentage fat comsumption increased with age in the Pan Yu residents, perhaps re¯ecting an

a

Score 4 for male, score 3 for female. Chi-square: 62.359, P < 0.001.

lowest in Hong Kong (Table 3). When the dietary pattern was examined by age group, for all age groups, Pan Yu had the highest percentage of subjects with a high score (Table 4). For all age groups, the dietary pattern was worst in Hong Kong. In summary, the results show considerable variations in Table 3

Mediterranean score in different regions by sex Mediterranean score high scorea

Sex Femaleb

Malec

Place

n

Count

%

Hong Kong Pan Yu San Francisco Sydney Hong Kong Pan Yu San Francisco Sydney

510 95 192 73 500 58 166 95

360 81 147 58 252 56 117 61

71 85 77 79 50 97 70 64

a

Score 4 for male; score 3 for female. Pearson chi-square 11.174; P 0.011. c Pearson chi-square 59.325; P < 0.001. b

Table 4

Mediterranean score in different regions by age group Mediterranean score high scorea

Age group b

34 or below

35 ± 54c

55 or aboved

Place

n

Count

%

Hong Kong Pan Yu San Francisco Sydney Hong Kong Pan Yu San Francisco Sydney Hong Kong Pan Yu San Francisco Sydney

209 66 56 22 543 48 201 115 258 39 101 31

108 55 35 13 338 46 154 80 166 36 75 26

51 83 63 59 62 96 77 70 64 92 74 84

a

Score 4 for male; score 3 for female. Pearson chi-square 21.115, P < 0.001. c Pearson chi-square 34.402; P < 0.001. d Pearson chi-square 17.014; P < 0.001. b

European Journal of Clinical Nutrition


increase in income. Elsewhere it has been documented that the consumption of fat and meat in China increases with improvement in socioeconomic status (Ge et al, 1995). In contrast, Hong Kong is entirely urban, and exposed to Western in¯uences from other countries. Yet the dietary habit of the population appears worse than that of Chinese populations in Sydney or San Francisco. A difference in socioeconomic status or a lower level of public health knowledge regarding nutrition and disease in Hong Kong may account for the difference. It is also possible that the lifestyle in Hong Kong, particularly for men and the young and middle-aged groups, consists of eating away from home much of the time, the fast food outlets being a regular source of meals for a large percentage of the population. In general, there is less geographical variation in dietary habits among the older population, perhaps re¯ecting a habit of taking more traditional Chinese meal patterns rather than adopting `Westernized' foods. The gender difference in dietary habits in Hong Kong is of interest. Young and middle-aged women had a better pattern compared with men. This may be a difference in lifestyle, in that more women may stay at home to look after children, or that women have better nutritional knowledge than men. Since meals are largely provided by women, one would not have expected a marked gender difference if men ate most of the meals at home (if they were not single). Just as there are variations in Mediterranean dietary patterns in populations in countries around the Mediterranean (Ferro-Luzzi & Branca, 1995), variations exist for the Chinese diet. The public health implications are that Chinese populations living in Western countries appear to have healthier dietary habits than urban populations in China. Therefore it is probably not necessary to particularly promote the traditional Chinese diet for health bene®ts in Chinese populations in Western countries. Indirectly this observation re¯ects the impact of public health programmes in these countries. However there is a need to raise the level of nutritional knowledge for Chinese populations in urban and socioeconomically advanced cities in China, such as Hong Kong, where the worst patterns occur in the younger and middle age groups. Since there are adverse features of the Chinese diet with respect to blood pressure and osteoporosis (high salt and low calcium content) (Woo et al, 1999), the standard dietary advice in the form of food pyramids (US Department of Agriculture, 1992; Willet et al, 1995) that is widely used in Western countries would be equally appropriate for the Chinese population in China. There are limitations for this study. The number of subjects in Pan Yu, Sydney and San Francisco may be too small in each age and sex group to detect any age and gender differences in dietary habits within each city. Also, the sampling method is different for the four geographical areas. The sample in Hong Kong is representative of the Hong Kong population (Woo et al, 1998). However, it is uncertain and dif®cult to determine `representativeness' of Chinese populations living overseas. Similarly we were not able to comment on whether the Pan Yu subjects are

representative of the whole of the Pan Yu district. Nevertheless, the strength of the study lies in that the same dietary assessment instrument had been used in all four regions, and was administered by the same team of interviewers. In spite of the limitations, one can conclude that currently the large majority of the Chinese population consume a diet comparable to the traditional Mediterranean diet, whether in China or in Western countries, and by extrapolating from the data for Mediterranean diet, are likely to have health bene®ts in terms of coronary heart disease and survival. However, the adverse features of the Chinese diet have not been taken into account. There is need for improved nutritional knowledge in urban Chinese populations in China, in order to prevent a worsening trend in dietary habits.

219

Acknowledgements ÐThis study is partially supported by the Bristol Myers Squibbs Foundation Unrestricted Nutrition Grant, and the Hong Kong Heart Foundation.

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