Levels of cardiovascular disease risk factors in Singapore following a national intervention programme.

Research Theme Paper Levels of cardiovascular disease risk factors in Singapore following a national intervention programme Jeffery Cutter,1 Bee Yian Tan,2 & Suok Kai Chew3 Objective To evaluate the impact of the National Healthy Lifestyle Programme, a noncommunicable disease intervention programme for major cardiovascular disease risk factors in Singapore, implemented in 1992. Methods The evaluation was carried out in 1998 by the Singapore National Health Survey (NHS). The reference population was 2.2 million multiracial Singapore residents, 18–69 years of age. A population-based survey sample (n = 4723) was selected by disproportionate stratified and systematic sampling. Anthropometric and blood pressure measurements were carried out on all subjects and blood samples were taken for biochemical analysis. Findings The 1998 results suggest that the National Healthy Lifestyle Programme significantly decreased regular smoking and increased regular exercise over 1992 levels and stabilized the prevalence of obesity and diabetes mellitus. However, the prevalence of high total blood cholesterol and hypertension increased. Ethnic differences in the prevalence of diabetes mellitus, hypertension, and smoking; and in lipid profile and exercise levels were also observed. Conclusion The intervention had mixed results after six years. Successful strategies have been continued and strengthened. Keywords Cardiovascular diseases/etiology/; Risk factors; Diabetes mellitus/epidemiology/ethnology; Hyper- tension/epidemiology/ethnology; Obesity/epidemiology/ethnology; Smoking/epidemiology/ethnology; Exercise; Ethnic groups; Life style; National health programs; Cross-sectional studies; Singapore (source: MeSH ). Mots cle´s Cardiovasculaires, Maladies/e´tiologie; Facteur risque; Diabe`te/e´pide´miologie/ethnologie; Hyper- tension arte´rielle/e´pide´miologie/ethnologie; Obe´site´/e´pide´miologie/ethnologie; Tabagisme/e´pide´miologie/ethno- logie; Exercice physique; Groupes ethniques; Style vie; Programme national sante´; Etude section efficace; Singapour (source: INSERM ). Palabras clave Enfermedades cardiovasculares/etiologı´a; Factores de riesgo; Diabetes mellitus/epidemiologı´a/ etnologı´a; Hipertensio´n/epidemiologı´a/etnologı´a; Obesidad/epidemiologı´a/etnologı´a; Tabaquismo/epidemiologı´a/ etnologı´a; Ejercicio; Grupos e´tnicos; Estilo de vida; Programas nacionales de salud; Estudios transversales; Singapur (fuente: BIREME ). Bulletin of the World Health Organization, 2001, 79: 908–915. Voir page 914 le re´sume´ en franc¸ais. En la pa´gina 914 figura un resumen en espan˜ol. Introduction The island of Singapore has undergone rapid socio- economic development since independence in 1965. For example, the per capita gross national product, adjusted to 1998 prices, rose from S$ 1618 in 1965 to S$ 38 170 in 1998 (US$ 1.0 = S$ 1.70). In 1998, the infant mortality rate was 4.1 per 1000 live births and life expectancy at birth was 79 years for females and 75 years for males. Other 1998 indicators include an adult literacy rate of 93% and 13 doctors per 10 000 population (1). The total population of Singapore in 1998 was 3.87 million and it had the second highest population density in the world (after Hong Kong Special Administrative Region of China) at 5965 people per km2. The resident population consisted of 77% Chinese, 14% Malay, 7.6% Indian, 1 Deputy Director, Non-Communicable Diseases, Epidemiology & Disease Control Division (E&DC), Ministry of Health, College of Medicine Building, 16 College Road, Singapore 169854 (email: jeffery_cutter@moh.gov.sg). Correspondence should be addressed to this author. 2 Deputy Director, Biostatistics & Research, E&DC, Ministry of Health, Singapore. 3 Director, E&DC, Ministry of Health, Singapore. Ref. No. 00-0677 908 # World Health Organization 2001 Bulletin of the World Health Organization, 2001, 79 (10) and 1.4% other ethnic groups. The main causes of mortality in Singapore mirrored those of developed countries, with cancer, ischaemic heart disease, and cerebrovascular disease responsible for 57% of all deaths in 1998 (2). These three diseases have been the main causes of death in Singapore since the 1970s. In 1991, a national committee was appointed to review the national health plan for the 1990s, and one of the key recommendations emphasized health promotion and disease prevention (3). This was followed by the National Healthy Lifestyle Pro- gramme in 1992, which adopted a multisectoral approach involving government ministries and organizations, health professionals, employers, un- ions, and community organizations. These sectors worked together to provide information, skills training, and the social and physical environment necessary to encourage healthy living by Singapor- eans. The programme included extensive use of the mass media to promote healthy lifestyles, legislative measures to discourage smoking, and widespread school, workplace, and community health promotion programmes. The programmes emphasized healthy diets, regular physical exercise, and measures to discourage smoking. In 1992, the Ministry of Health also conducted the firstNationalHealth Survey (NHS), a population- based cross-sectional survey to measure the pre- valence of diabetes mellitus, hypertension, obesity, smoking, physical inactivity, and hypercholestero- laemia — all cardiovascular disease risk factors. Findings from the survey provided baseline data for subsequent evaluation of the effectiveness of the National Healthy Lifestyle Programme. In 1998, six years after the launch of the National Healthy Lifestyle Programme, a second NHS was conducted to determine whether the risk factors in the population had changed. Methods The NHS was a cross-sectional survey conducted between September and November, 1998. The reference population was 2.16 million Chinese, Malay, and Indian Singapore residents aged 18– 69 years. Six centres around the island of Singapore were selected as field sites for the survey. Details of the survey methodology have been described else- where (4). Determination of sample size We calculated that a sample size of 5000 respondents would be required to detect a 10–15% change from baseline for most of the diseases and risk factors with 80% power. The prevalence of diabetes mellitus, hypertension, and other cardiovascular risk factors (obesity, smoking, and physical inactivity) measured in the 1992 NHS was used as baseline levels. To account for potential non-response during the survey, we estimated that at least 10 000 households would need to be approached to obtain the target sample size. Sample selection The sample selection was divided into two phases. In phase I, a sample of 11 200 household addresses was selected from the National Database on Dwellings. The sample selection was based on a modified two- stage stratified design. For the first stage, sampling divisions close to the six selected survey centres were chosen and households within each division were stratified by house type (a proxy for socioeconomic status) and systematically selected in the second stage. The final sample of 11 200 addresses repre- sented the housetype distribution for the entire Singapore housing population. This was followed up by house visits to enumerate all household members aged 18–69 years. In phase II, a random sample of 7500 people was selected by disproportionate stratified and systematic sampling of household members identi- fied in phase I. The Malays and Indians were oversampled, to ensure that prevalence estimates for these minority groups were reliable. The ethnic composition of the sample was 64% Chinese, 21% Malays, and 15% Indians. Survey protocol and procedures The survey protocol closely followed that of the 1992 NHS to ensure comparability. The NHS protocol was based on the WHO-recommended model for field surveys of diabetes and other noncommunic- able diseases (5) and the WHO MONICA (Multi- national Monitoring of Trends and Determinants in Cardiovascular Disease) protocol for population surveys (6). Subjects were instructed to fast over- night for at least 10 hours before coming to the designated survey centre. A fasting blood sample was collected and all subjects, except diabetics on medication, had an oral glucose tolerance test (7). Other procedures included measuring blood pres- sure, height, weight, waist and hip circumference, and the administration of a structured questionnaire. The 1985 WHO diagnostic classification criteria (7)wereused toclassifyglucose tolerance.Self-reported diabetics onmedication were also taken to be diabetics. Blood-pressure measurements followed procedures prescribed in the WHO MONICA protocol (6). Carefully trained observers took two measurements in a quiet room after the subjects were rested. Hyper- tension was defined according to WHO criteria: mean systolic pressure 5140 mmHg; or diastolic pressure (phase V) 590 mmHg; or both; or self-reported current use of antihypertensive medication (8). Smoking status and level of physical activity were determined by questionnaires, which were administered by interviewers according to WHO guidelines (9) and the American College of Sports Medicine’s classification (10). Body mass index (BMI) was measured as weight (kg)/height (m)2. The WHO classification of weight status and abdominal fatness was used (11). The means of two readings of height and weight, as well as waist and hip circumferences, were used to calculate the bodymass index and waist:hip ratio, respectively. Cholesterol 909Bulletin of the World Health Organization, 2001, 79 (10) Levels of cardiovascular disease risk factors in Singapore level was classified according to that set by the United States National Institutes of Health (12). Information recorded on the questionnaires was manually checked for missing values, data-entry errors, and inconsistency. Data anomalies were checked and amended following direct contact with the participants by telephone. The survey database was subjected to further consistency and verification checks built into the computer system. Laboratory methods All blood specimens for plasma glucose measure- ment were collected in fluoride/oxalate tubes, centrifuged on site, and sent to the Biochemistry Laboratory of the Department of Pathology, Singapore General Hospital for analysis on the same day. Specimens for cholesterol measurement were collected in plain tubes. Plasma glucose levels, total blood cholesterol, and high-density-lipo- protein (HDL)-cholesterol were measured on a BM/Hitachi 747/737 analyser by the enzymatic colorimetric method. Low-density-lipoprotein (LDL)-cholesterol was measured by the homoge- nous turbidimetric method. Because different methods were used to assay HDL-cholesterol in 1992 and 1998, the 1998 measurements were adjusted downwards using a regression equation. In 1992, HDL-cholesterol was measured by first precipitating LDL-cholesterol and very-low-den- sity-lipoprotein (VLDL)-cholesterol, and then as- saying HDL with a Kodak 700 analyser. In 1998, in contrast, HDL-cholesterol was measured directly using a BM/Hitachi 747/737 analyser. Statistical analysis Statistical analyses were performed using the Statis- tical Analysis System (13). The survey data were weighted by the age, ethnic group, and sex distribu- tion of the 1998 Singapore resident population. Prevalence was age-standardized directly, using the 1990 Singapore resident population as the standard (as 1990 was a census year). Changes in age- standardized prevalence levels between 1992 and 1998 were tested for statistical significance using the z-test (14) and 95% confidence limits were calcu- lated. Survey subjects From the original sample of 7500 adults, 175 people had to be excluded due to pregnancy, death, or being overseas during the survey period. The survey yielded a response rate of 64.5% (4723/7325). A comparison of respondents and non-respondents showed that respondents had a higher representation of females and Chinese, a lower proportion of young adults in the 18–29-year age group, and a lower proportion of people living in smaller public flats (Table 1). Weighting the survey sample To correct for oversampling of minority ethnic groups in the survey and differential response levels, the survey sample was weighted to the age, ethnic group, and gender distribution of 1998 resident population estimates (1). This ensured that the survey results were representative of the general population in terms of age, ethnic group, and gender distribution. In Table 2, the socio- economic characteristics (in terms of house type) of the weighted survey sample are compared with those of the 1998 Singapore resident population. This showed that the weighted survey sample contained proportionately fewer people who lived in the smaller public flats. Results Prevalence levels of cardiovascular disease risk factors are reported for the population aged 18– 69 years, except the prevalence for hypertension, which is reported for the population aged 30– 69 years. Diabetes mellitus and hypertension The age-standardized prevalence of diabetes melli- tus among Singapore residents aged 18–69 years did not change significantly between 1992 (8.4%) and 1998 (8.1%) (P >0.05; Table 3). Nor was there any change in the prevalence of impaired glucose tolerance (13.9%). However, the prevalence of hypertension increased in the population aged 30– 69 years, from 22.5% in 1992 to 26.6% in 1998 (P <0.001). Obesity and lipid levels The prevalence of obesity (BMI 530kg/m2) was unchanged between 1992 (5.1%) and 1998 (5.9%; P = 0.076). In contrast, the prevalence of high total blood cholesterol (56.2 mmol/l) increased from 19% in 1992 to 23.5% in 1998 (P <0.001), and was greater for men (a 30% rise) than women (17% rise). For both men and women, the mean total blood cholesterol also increased from 5.3 mmol/l to 5.5 mmol/l. In the same period, the prevalence of high LDL-cholesterol (54.1 mmol/l) increased from 22.7% to 24.6% (P = 0.044), while the prevalence of low HDL-cholesterol (<0.9 mmol/l) was essentially unchanged (1992: 6.0%; 1998: 5.2%; P = 0.084). Cigarette smoking The prevalence of regular cigarette smoking (at least once a day) by men decreased from 33.5% in 1992 to 26.5% in 1998 (P <0.001). Although no significant change was observed for women, the prevalence of regular cigarette smoking was already very low (1992: 2.9%; 1998: 3.2%; P >0.05). For both men and women combined, the prevalence of regular smoking decreased from 18.4% to 15.0% between 1992 and 1998 (P <0.001). In contrast, regular smoking among young women aged 20–24 years increased almost threefold, from 2.5% to 6.7% (P <0.05). 910 Bulletin of the World Health Organization, 2001, 79 (10) Special Theme – Noncommunicable Diseases Regular exercise The proportion of Singapore residents who exercised regularly (at least three times a week for at least 20 minutes per session) increased from 13.6% to 16.9% between 1992 and 1998 (P <0.001). The changewas attributed to an increase in the proportion ofwomenwho exercised regularly (1992: 8.1%; 1998: 13.2%; P <0.001). There was no significant change for men (1992: 19.0%; 1998: 20.5%; P >0.05). Ethnic differences Differences were observed in the prevalence of all cardiovascular disease risk factors studied among the three major ethnic groups, Chinese, Malays, and Indians (Table 4). Indians had the highest prevalence of diabetes mellitus (age-standardized prevalence: 14.5%; 10.7% in Malays; 7.0% in Chinese), while Malays had the highest prevalence of hypertension (age-standardized prevalence: 32.3%; 26.0% in Chinese; 23.7% in Indians). Obesity prevalence was low among the Chinese (3.8%), compared to Malays (15.3%) and Indians (12.3%). Malay and Indian women had an especially high prevalence of obesity (22.0% and 17.5%, respectively), compared to Chinese women (3.0%). High total blood cholesterol was more pre- valent in Malays (34.0%), compared to Chinese (21.8%) and Indians (23.0%). Malays also had the highest prevalence of cigarette smoking (men: 42.9%; women: 3.7%; Chinese men: 23.4%; Chinese women: 3.3%; Indian men: 29.3%; Indian women: 0.8%). On the other hand, more Indians (25.0%) and Malays (19.3%) exercised regularly compared to Chinese (15.8%). Between 1992 and 1998, the prevalence of hypertension and high total blood cholesterol rose significantly among the Chinese and Malays, but not the Indians. Likewise, the prevalence of regular smoking decreased significantly only among the Chinese andMalays. All three ethnic groups recorded significant increases in regular exercise, and only in Malays was there a significant increase in the prevalence of obesity. Discussion Validity of the study The number of subjects was close to the sample size needed to detect a 10–15% change from baseline, even though the response rate was only 65%. This was achieved by factoring in the likely response rate, based on the 1992 survey. Among survey respon- dents, there were higher proportions of females and Chinese, a lower proportion of young adults (aged 18–29 years) and a lower proportion of people living in smaller public flats, compared to non-respondents. The survey sample was weighted to the population age, sex, and ethnic group distribution. After weighting, the proportion of people in the sample who lived in smaller public flats (22.4%) was lower than in the resident population (30.5%). As this difference was not large, it is likely that this introduced minimal bias into risk factor prevalence estimates. There may have been underreporting of cigarette smoking and overreporting of physical exercise, as these measures were self-reported. To minimize these potential biases, the same questions relating to these measures were used in both the 1992 and 1998 surveys and interviewers were carefully trained. Misclassification of blood pressure status was minimized by using a standard protocol and repeat measurements, and the same carefully trained nurses measured blood pressure throughout the survey. Table 1. Comparison of the unweighted survey sample, non- respondents, and the 1998 resident Singapore population Characteristics Survey Survey Mid–1998 respondents non- resident (unweighted %) respondents population n = 4723 (%) (%) n = 2602 n = 2 155 600 Sex Male 46.2 54.2 50.1 Female 53.8 45.8 49.9 Age (years) 18–29 25.5 32.3 26.1 30–39 32.0 31.5 28.0 40–49 24.6 9.5 24.3 50–59 10.6 9.2 13.4 60–69 7.3 7.5 8.2 Ethnic group Chinese 68.3 57.4 79.9 Malay 18.0 26.1 12.7 Indian 13.7 16.5 7.4 House type Public flat (1–3 rooms) 23.5 33.2 30.5 Public flat (4 rooms) 37.4 33.9 33.6 Public flat (55 rooms) 23.3 17.0 19.4 Private houses and flats 15.8 15.9 16.5 Total 100.0 100.0 100.0 Table 2. Comparison of house type of survey respondents (weighted) and 1998 resident population House type Respondents 1998 resident (weighted %) populationa (%) n = 4723 Public flat (1–3 rooms) 22.4 30.5 Public flat (4 rooms) 36.7 33.6 Public flat (55 rooms) 23.6 19.4 Private houses and flats 17.3 16.5 Total 100.0 100.0 a Data from the house-type distribution of the random sample of eligible household units selected in the enumeration phase of the National Health Survey in 1998. 911Bulletin of the World Health Organization, 2001, 79 (10) Levels of cardiovascular disease risk factors in Singapore Intervention programme The goals of the 1992 National Healthy Lifestyle Programme in Singapore were to reduce smoking prevalence, increase exercise participation, and promote healthy diets among the population. An intensive month-long healthy lifestyle campaign, with activities in community venues, schools, and workplaces was held annually to supplement ongoing programmes. The Prime Minister led thousands of Singaporeans in mass exercise events in launching these campaigns and the mass media promoted healthy lifestyles throughout the year. To harness greater community involvement, a civic committee was appointed to oversee the National Healthy Lifestyle Programme from 1996, and was composed of members from both the public and private sectors, as well as voluntary organizations. Table 3. Age-standardizeda prevalence of major factors influencing cardiovascular disease risk, 1992 and 1998 Risk factor Prevalenceb (%) Significancec Men Women Total 1992 1998 Difference 1992 1998 Difference 1992 1998 Difference Men Women Total n = 1803 n = 2181 n = 1765 n = 2542 n = 3568 n = 4723 Diabetes mellitus 8.6 7.7 –0.9 8.1 8.4 0.3 8.4 8.1 –0.3 NS NS NS Impaired glucose tolerance 13.9 14.0 0.1 13.9 13.7 –0.2 13.9 13.9 0.0 NS NS NS Hypertensiond 26.2 30.2 4.0 18.7 23.0 4.3 22.5 26.6 4.2 * ** *** Obesitye 4.0 5.2 1.2 6.2 6.6 0.4 5.1 5.9 0.8 NS NS NS High total blood cholesterol levelf 19.7 25.6 5.9 18.2 21.3 3.1 19.0 23.5 4.5 *** ** *** Smokingg 33.5 26.5 –7.0 2.9 3.2 0.3 18.4 15.0 –3.4 *** NS *** Regular exerciseh 19.0 20.5 1.5 8.1 13.2 5.1 13.6 16.9 3.3 NS *** *** a Age-standardized to the 1990 Singapore resident population. b The prevalence of all risk factors is for people aged 18–69 years, except for hypertension which is for people aged 30–69 years. c NS = not significant at the P = 0.05 level; * 0.01 < P < 0.05; ** 0.001 < P < 0.01; *** P < 0.001. d Blood pressure5140/90 mmHg. e BMI530 kg/m2. f Total blood cholesterol > 6.2 mmol/l. g At least 1 cigarette a day. h At least 3 times a week; 20 minutes per session. Table 4. Age-standardizeda prevalence of major factors influencing cardiovascular disease risk in 1998 by ethnic group Risk factor Prevalenceb (%) Chinese Malay Indian Men Women Total Men Women Total Men Women Total n = 1470 n = 1758 n = 3228 n = 404 n = 445 n = 849 n = 307 n = 339 n = 646 Diabetes mellitus 7.0 (5.7–8.2)c 7.1 (5.9–8.3) 7.0 (6.2–7.9) 8.5 (6.1–10.8) 12.9 (10.2–15.7) 10.7 (8.9–12.5) 14.5 (11.3–17.6) 14.6 (11.6–17.6) 14.5 (12.4–16.7) Impaired glucose tolerance 13.4 (11.7–15.2) 12.7 (11.2–14.2) 13.1 (11.9–14.2) 19.3 (15.5–23.2) 19.0 (15.5–22.5) 19.2 (16.6–21.8) 10.5 (7.5–13.5) 15.6 (11.7–19.6) 13.0 (10.6–15.5) Hypertensiond 30.9 (28.3–33.4) 20.9 (18.9–23.0) 26.0 (24.3–27.6) 28.6 (23.8–33.5) 36.0 (31.5–40.4) 32.3 (29.0–35.5) 26.3 (21.1–31.4) 21.1 (17.1–25.1) 23.7 (20.4–27.0) Obesitye 4.5 (3.4–5.6) 3.0 (2.2–3.8) 3.8 (3.1–4.4) 8.7 (6.0–11.4) 22.0 (18.2–25.8) 15.3 (12.9–17.6) 7.2 (4.1–10.3) 17.5 (13.4–21.5) 12.3 (9.7–14.8) High total blood cholesterolf 23.3 (21.3–25.4) 20.2 (18.4–21.9) 21.8 (20.4–23.1) 38.4 (33.7–43.1) 29.4 (25.7–33.1) 34.0 (31.0–36.9) 26.7 (21.8–31.7) 19.1 (14.9–23.3) 23.0 (19.7–26.2) Smokingg 23.4 (21.2–25.7) 3.3 (2.4–4.2) 13.5 (12.3–14.7) 42.9 (37.8–48.0) 3.7 (2.0–5.5) 23.6 (20.9–26.3) 29.3 (23.6–35.0) 0.8 (0.0–1.8) 15.3 (12.3–18.2) Regular exerciseh 19.1 (17.0–21.1) 12.4 (10.9–14.0) 15.8 (14.5–17.1) 23.5 (19.2–27.8) 14.9 (11.5–18.2) 19.3 (16.5–22.0) 31.2 (25.3–37.0) 18.7 (14.3–23.0) 25.0 (21.3–28.7) a–b See footnotes a–b, Table 3. c Figures in parentheses are 95% confidence intervals. d–h See footnotes d–h, Table 3. 912 Bulletin of the World Health Organization, 2001, 79 (10) Special Theme – Noncommunicable Diseases Successes and failures Singapore’s approach in targeting the population at large appears to have hadmixed results after six years. Notable successes were in reducing the rate of cigarette smoking among men, and increasing the proportion of people who exercised at least three times a week. However, smoking prevalence among young women aged 20–24 years rose, this being probably part of a trend seen in many countries. Increases in the prevalence of cigarette smoking among young women have been reported in Japan (15) and the USA (16). It is possible that smoking prevalence rose in this group as more young women rebelled against pervasive anti-smoking messages. The programme was unsuccessful in reducing total blood cholesterol levels. The 1998 National Nutrition Survey reported that the dietary habits of Singaporeans changed between 1993 and 1998 (17). In 1993, only 72% of adult Singaporeans trimmed some or all visible fat when eating meat, compared to 87% in 1998. More people also partly or completely trimmed poultry skin in 1998 (81% vs 60% in 1993). However, the proportion consuming deep-fried foods three or more times a week remained about the same (approximately 45%). There was also no change in the pattern of cooking oil use. In 1998, the proportions of people who used either blended cooking oils, polyunsaturated oils, or monounsatu- rated oils most of the time were about the same as in 1993 (43%, 42%, and 13%, respectively). The apparent success of the programme in reducing smoking and increasing exercise could be due to the multipronged strategy in these two areas, especially for smoking. Besides the mass media blitz, the smoking control programme employed legislative measures. A ban on all forms of cigarette advertising was continued and the number of public places where smoking was banned was also increased. In 1994, for example, smoking was banned in all air-conditioned offices and factories, and in taxi and bus queues in 1995. Fiscal measures (i.e. increasing tobacco taxes) increased the price of cigarettes and well-known sportsmen and television personalities were used as role models to discourage smoking. Messages in the mass media to exercise regularly were reinforced by mass exercise events, such as the annual Great Singapore Workout, led by the Prime Minister. On the other hand, public education to adopt healthier diets reliedmainly onmessages in themassmedia and on exhibitions. Public education efforts to reduce cholesterol intake, for example, focused on sub- stituting or eliminating foods high in fat or cholesterol from the diet. Similar interventions elsewhere Multipronged strategies have also been successful in Finland and Mauritius. Between 1972 and 1992, dietary changes in the North Karelia province of Finland reduced themean total serum cholesterol level in men by 16% (a decrease of 1.07 mmol/l). For example, the prevalence of high-fat milk consumption dropped from 70% to 14% among men and from nearly 60% to 10% among women. The North Karelian project was successful because the pro- grammes were carefully monitored and were respon- sive to changing community situations. The project also stressed efforts to teach practical skills for change, such as ways of buying and cooking healthier foods. The food and retail industries were also involved in producing and marketing healthier foods, thereby increasing their availability to the general public (18). In Mauritius, the mean population serum cholesterol level fell from 5.5 mmol/l in 1987 to 4.7 mmol/l in 1992, after five years of a nationwide noncommunicable disease intervention programme coordinated by the Mauritius Ministry of Health. The improvement in the population lipid profile was attributed to a change from using a local cooking oil rich in palm oil to one with almost 100% soybean oil, with its lower saturated fat content (19). This demonstrated that dramatic effects could be brought about by measures other than public health education. In most countries, healthy lifestyle pro- grammes, such as those aimed at stopping smoking and adopting regular exercise, are based on public education without intensive annual campaigns, such as those carried out in Singapore. This may be due to the logistical difficulties of organizing annual cam- paigns in large countries. Nonetheless, smoking rates among adults in the USA declined steadily from the mid-1960s through to the 1980s, before levelling off in the 1990s at about 25% (20). The proportion of adults in the USA who engaged in vigorous physical activity at least three times a week also rose from 15% in 1991/92 (21) to 23% in 1997 (22). In England, the prevalence of cigarette smoking among people aged 16 years or older fell from 31% in 1991/92 (23) to 27% in 1999 (24). Over the same period, the mean total blood cholesterol level in the population also fell from 5.8 mmol/l to 5.5 mmol/l in men, and from 5.9 mmol/l to 5.6 mmol/l in women (23, 24). Current interventions in Singapore TheMinistry of Health in Singapore has reviewed the strategies used between 1992 and 1998 to reduce the prevalence of cardiovascular disease risk factors in the population. Successful strategies have been continued and strengthened. New strategies have included targeting higher-risk groups for education and other intervention programmes, increasing community participation, and intensifying pro- grammes to promote health in the workplace. The food industry has been involved to a greater extent to help promote healthier dietary habits, such as by providing nutritional information at the point of sale, including nutrition labels and nutrition information at eateries. The promotion of healthier food choices in eateries has also been expanded. Media messages on healthy lifestyles have continued, but have beenmore focused. n Conflicts of interest: none declared. 913Bulletin of the World Health Organization, 2001, 79 (10) Levels of cardiovascular disease risk factors in Singapore Re´sume´ Evolution des facteurs de risque cardio-vasculaire a` Singapour a` la suite d’un programme national d’intervention Objectif Evaluer l’impact du National Healthy Lifestyle Programme, un programme d’intervention contre les maladies non transmissibles axe´ sur les principaux facteurs de risque de maladie cardio- vasculaire a` Singapour, mis en œuvre en 1992 dans le but de promouvoir des modes de vie favorables a` la sante´. Me´thodes L’e´valuation a e´te´ re´alise´e en 1998 dans le cadre d’une enqueˆte nationale sur la sante´ (Singapore National Health Survey). La population de re´fe´rence, multiraciale, se composait de 2,2 millions d’habitants de Singapour aˆge´s de 18 a` 69 ans. Pour l’enqueˆte en population, un e´chantillon (n = 4723) a e´te´ constitue´ selon une me´thode d’e´chantillonnage syste´matique de type stratifie´ non proportionnel. Les parame`tres anthropome´triques et la tension arte´rielle ont e´te´ mesure´s sur tous les sujets et des pre´le`vements de sang ont e´te´ re´alise´s pour les analyses biochimiques. Re´sultats Les re´sultats de 1998 laissent a` penser que le National Healthy Lifestyle Programme a re´duit de fac¸on significative le tabagisme re´gulier et augmente´ la pratique re´gulie`re de l’exercice physique par rapport aux valeurs de 1992, et stabilise´ la pre´valence de l’obe´site´ et du diabe`te sucre´. En revanche, la pre´valence de l’hypercholeste´role´- mie (choleste´rol total) et de l’hypertension a augmente´. Des diffe´rences interethniques au niveau de la pre´valence du diabe`te sucre´, de l’hypertension et du tabagisme ainsi qu’au niveau du profil lipidique et de l’exercice physique ont e´galement e´te´ observe´es. Conclusion Six ans apre`s le de´but de l’intervention, les re´sultats sont variables. Les strate´gies re´ussies seront poursuivies et renforce´es. Resumen Magnitud de los factores de riesgo cardiovascular en Singapur tras un programanacional de intervencio´n Objetivo Evaluar el impacto del Programa Nacional de Modos de Vida Sanos, una intervencio´n empren- dida en 1992 en el a´mbito de las enfermedades no transmisibles con objeto de controlar los principales factores de riesgo de enfermedad cardiovascular en Singapur. Me´todos La evaluacio´n se llevo´ a cabo en 1998 como parte de la Encuesta Sanitaria Nacional (NHS) de Singapur. La poblacio´n de referencia estaba constituida por 2,2 millones de residentes en Singapur de diversas etnias entre 18 y 69 an˜os de edad. Se selecciono´ una muestra encuestal basada en la poblacio´n (n = 4723) mediante te´cnicas de muestreo estratificado y sistema´- tico no proporcional. Se efectuaron mediciones antropo- me´tricas y de la tensio´n arterial en todos los individuos y se tomaron muestras de sangre para someterlas a ana´lisis bioquı´micos. Resultados Los resultados de 1998 parecen indicar que el Programa Nacional de Modos de Vida Sanos redujo significativamente el tabaquismo regular y aumento´ la pra´ctica habitual de ejercicio respecto a los niveles de 1992, y adema´s estabilizo´ la prevalencia de obesidad y de diabetes mellitus. Sin embargo, aumento´ la prevalencia de colesterolemia y de hipertensio´n. Se observaron asimismo diferencias e´tnicas en cuanto a la prevalencia de diabetes mellitus, hipertensio´n y taba- quismo, perfil lipı´dico y niveles de ejercicio. 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