I 882 Am J Cli,: Nuir 1997:65:1882-6. Printed in USA. 1997 American Society for Clinical Nutrition

Heart disease risk-factor status and dietary changes in theCretan population over the past 30 y: the Seven CountriesStudy13Anthony Kafatos, Anastasia Diacatou, George Voukiklaris, Nick Nikolakakis, John Vlachonikolis,Daphne Kounali, George Mamalakis, and Anastasios S Dontas

ABSTRACT A follow-up study was conducted to identify theheart disease risk-factor status and dietary changes of surviving

elderly subjects in Crete who took part in the Seven CountriesStudy in 1960. In 1991 , data were obtained from 245 of the 686original male participants (169 of the original 40-49-y age groupand 76 men from the 50-59-y age group). In 1991, the men were70-79 and 80-89 y old. There was a significant ( I I .5%) increasein serum total cholesterol concentrations between 1960 and 1991.

Body mass index and systolic and diastolic blood pressures alsoincreased significantly, and all age groups were characterized bycentral obesity. A representative subsample of 2 1 men took part ina 3-d weighed food record study. Dietary data indicated increasesin the intake of saturated fat and decreases in monounsaturated fat

over the 30-y period. Comparison with a 1962 representativeCretan sample indicated a significantly increased concentration ofadipose palmitic acid ( I 6:0) in our surviving sample. The observedchanges occurred during a period when many developed countrieswere observing a decline in most heart disease risk factors.A,n J C/in Nuir 1997:65:1882-6.

KEY WORDS Crete, Seven Countries Study, cholesterol,diet, heart disease, elderly people, monounsaturated fat, satu-rated fat, risk factors

INTRODUCTION

The diet-cholesterol-heart disease hypothesis has been testedby many studies in the second half of this century ( I , 2). TheFramingham Study and the Seven Countries Study are amongthe longest and the most important studies, providing thefoundation for our contemporary primary heart disease preven-tion programs (3, 4). In the Seven Countries Study, Crete wasthe area with the lowest heart disease prevalence and incidence.Some of the reasons proposed for this outstanding finding werelow serum cholesterol concentrations, high physical activity,and consumption of a diet that was low in saturated fat and highin monounsaturated fat. The present study reports the 3O-yfollow-up of the surviving men in Crete compared with theoriginal findings in the early l960s.

SUBJECTS AND METHODS

The study was part of an international cooperative study oncardiovascular epidemiology that included cohorts in seven

countries. The original cohort was drawn in 1957 from 11

villages in the central part of the island of Crete. The Cretansample was initially tested in 1960 and was retested in 1965,1970, and 1991. There were 177 men that participated both inthe initial study and all subsequent follow-ups. The 1960 groupconsisted of 74 men aged 25-29 y, 363 men aged 40-49 y, and323 men aged 50-59 y. The men were engaged mainly infarming, either on a full-time or part-time basis. Our totalcohort in 1991 consisted of 245 men between 70 and 89 y ofage (aged 40-59 y in 1960). Of these men, 169 were between70 and 79 y of age (aged 40-49 y in I 960) and 76 werebetween 80 and 89 y (aged 50-59 y in 1960). We decided notto include the younger subsample (aged 25-29 y in 1960) in thestudy because data on this subsample were neither reported inoriginal publications nor available in the University of Minne-sota computer database. All subjects were informed about thenature and purpose of this study and signed a consent form.The ethical committee at the University of Crete had previouslyapproved the protocol of the study. The investigators assuredduplication of the original protocol with minor modifications:a short questionnaire related to the sociocultural status of theelderly subjects, bioelectrical impedance analysis and fundusexamination, adipose fat aspiration, a change in the dietaryintake and physical activity evaluation, and a change in thelocus of physical examination, which took place in the Uni-versity Hospital instead of in the subjects villages.

In the first part of this follow-up study data were collectedwith a codified questionnaire pertaining to daily activities,exercise, social activities, health, smoking, alcohol, dietaryinformation, and socioeconomic characteristics. The interviewswere carried out at home by a research team consisting ofdietitians, psychologists, visiting nurses, and a social worker.All men were able to provide answers for themselves, althoughthe spouse was also present in 50% of the interviews.

I From the Department of Social Medicine, University of Crete School

of Medicine, Iraklion, Crete, Greece.2 Supported by Sevitel (Greek Society of Olive Oil Exporters), the

European Economic Community through the Integrated MediterraneanPrograms, and the Greek Ministry of Health, Welfare and Social Services.

3 Address reprint requests to A Kafatos, Director of Preventive Medicineand Nutrition Clinic, School of Medicine, University of Crete, P0 BoxI 393 Iraklion, Crete. Greece. E-mail: Kafatos@med.uch.gr.

Received February 13. 1996.Accepted for publication January 23. 1997.

by guest on February 22, 2015ajcn.nutrition.org

Dow

nloaded from

HEART DISEASE AND DIETARY CHANGES IN CRETE I 883

In the second part of the study the subjects were transferredto the Preventive Medicine and Nutrition Clinic at the Univer-sity Hospital to undergo physical examinations. Blood wasdrawn from each subject after a I 2-h overnight fast. A spoturine sample was also obtained in the morning. After blooddrawing, body composition was measured by the bioelectricalimpedance method (BODYSTAT; BodyStat Corporation,Capetown, South Africa) before any coffee, orange juice, ormilk was consumed by the subjects. The rest of the measure-ments, such as anthropometric measurements, a videotape ofthe fundus, blood pressure measurement, a respiratory functiontest, and subcutaneous fat aspiration were performed after alight breakfast. Fifteen subjects were examined in their homesbecause they were unable to come to the University Hospital.

Anthropometric measurements

The methodology followed the original protocol (4). Allanthropometric measurements were taken by the same regis-tered nurse. Body weight was measured with a digital scale(Seca, Hamburg, Germany) with an accuracy of 100 g. Stand-ing height was measured with a stadiometer measuring to thenearest 0. 1 cm in subjects without shoes, with shoulders re-laxed, with arms hanging freely, and with heels adducted.Skinfold thicknesses, to the nearest 0.2 mm, were measuredtwice at the same site (the average of each site was used forfurther calculations) on the left side of the body by using theLange skinfold caliper (Cambridge Scientific Industries, Inc,Cambridge, MD), ensuring that only soft tissue was taken inthe fold without the underlying muscle. Body composition wasmeasured by the bioelectric impedance method.

Physical activity

A total physical activity score was derived from the summa-tion of responses to questions about the time spent in leisure-time activities (eg, walking, cycling, and gardening). Possibleanswer categories for each activity item, originally given astime intervals, were recoded and the midpoint of each categorywas taken as the category value (eg, 0.5-1 h was recoded as 45mm). Physical activity score (energy expenditure per week)was calculated by multiplying the time (in mm) of participationin physical activities per week by the energy expenditure indexfor each activity (5) by the subjects weight.

Blood pressure and blood analysis

The methodology for blood pressure and blood analysis wasthe same as that for the original protocol (4). Arterial bloodpressure measurements were taken with a mercury sphygmo-

manometer. Subjects rested 10 mm before blood pressuremeasurements. The width of the cuff was placed at the highest

possible part of the right arm, covering 50-75% of the area.The measurement was taken three times with a 2-3-mm inter-val between each reading. The mercury was allowed to fall 2mm/s. Final readings of systolic blood pressure were taken asthe mean values of the second and third measurements. Adi-pose tissue fatty acid analyses were made in a representativesubsample of 49 men. Adipose fat aspirates were analyzed byusing the method described by Katan et al (6).

Besides the internal quality control, the laboratory of theDepartment of Social Medicine participates in the WellcomeDiagnostic Laboratory external quality-control program. The

total serum cholesterol concentrations of our laboratory werewithin the prescribed 2 SD of the mean Wellcome values

during the period of the study (February-March 199 1 ). The SEof measurement of serum cholesterol by the Abell-Kendallmethod (7) was 2% of the mean value.

Dietary intake

A subsample of 21 subjects took part in a 3-d weighed foodrecord study. The subsample had been randomly selected fromthe 1991 sample via computer-generated random numbers. Thesubsample was between 70 and 89 y of age. Dietary data werecollected between March and May 1991 . Dietary intake inter-views were carried out at the subjects homes. All meals thatwere eaten throughout the day were weighed and recorded inthe households, as well as the time of consumption, cookingmethod, and kind and amount of raw products.

A dietitian was present daily in the households to explain thescale and how to weigh the food correctly, and to assistwhenever necessary. In addition to the edible parts of the rawproducts, the exact amount of prepared or cooked meal asubject had eaten was also measured.

The weight of the raw products was transformed to thecooked products weight by taking into account the change intheir water content by cooking. These data were analyzed bythe nutrient database program of the US Department of Agri-culture (release no. 8) (8), adjusted properly for Greek foods.Twenty unusual Greek dishes and 10 local cheeses were chem-ically analyzed by the Wageningen Agricultural University inthe Netherlands (Department of Human Nutrition). The foodswere precoded into I 8 different food categories: bread, cereals(rice, pasta, muesli, and barley cereals), potatoes, pulses, veg-etables, fruit, meat, fish, eggs, cheese, milk, edible fats, oliveoil, sugar products and pastries, 100% alcohol, nonalcoholicbeverages. coffee and tea, and nuts and almonds. The list ofprecoded foods was based on four different nutrition surveysearned out in the 1980s among different populations in Crete.Three hundred-fifty different foods commonly used by thepopulation surveyed were isolated. For Cretan foods not chem-ically analyzed, the code numbers of the ingredients were usedaccording to the recipe of preparation. To ensure the compat-ibility of the measure, the foods comprising each of the 18

different food subcategories in 1991 were kept similar to thosein 1960. Because no food-composition tables are available forGreece, data were analyzed by using the modified US Depart-ment of Agriculture database (8). We used the same databaseversion as that used in 1960 to ensure the compatibility of themeasures.

Statistical analysis

Comparisons of the mean values of continuous variables fortwo samples were carried out with two-tailed Students t tests.Whenever comparisons of mean values involved informationrecorded by reference data and original raw data were notavailable we used the Students statistic. Multiple comparisonsof mean values of continuous variables between classes ofinterest were made by analysis of variance (ANOVA). Van-ables with skewed distributions [high-density-lipoprotein(HDL) cholesterol, low-density-lipoprotein (LDL) cholesterol,triacylglycerols, and LDL] were tested for the null hypothesisthat these variables are a random sample from a normal distri-

by guest on February 22, 2015ajcn.nutrition.org

Dow

nloaded from

1884 KAFATOS ET AL

bution. The test statistic used was suggested by Shapiro andWilk (9). If the null hypothesis was rejected, correspondingvariable values were transformed by taking the natural loga-

rithms so that they could meet the assumptions needed for theANOVA to be applied. Moreover, to increase the precision indetermining the effect of the variable of interest (such as age),other variables suspected to be involved as confounders wereincluded in the model as covariates. In that case, comparisonswere carried out by analysis of covariance (ANCOVA).

ANOVA for repeated measures was performed to test po-tentially significant differences among mean values of contin-uous variables representing repeated measures of the same

experimental unit. The latter analysis also involved multifactorrepeated-measures designs when more than one interac-tion effect was necessary to be entered. Discrete data cross-classified in contingency tables were analyzed by the Mantel-

Haenszel chi-square test (two-way tables) (10). When no rawdata were available, the parametric test for the comparison ofproportions was used (based on the Z statistic) (1 1). To makedietary data more representative of the follow-up cohort, thebootstrap, a resampling technique, was used (the number ofbootstrap replicates generated was 100 000) ( 1 2). Data wereanalyzed with the SAS statistical software program (SAS In-stitute Inc, Cary, NC).

RESULTS

The follow-up data available for the same subjects (40-59-yagegroup)in l960andtheirvaluesin 1965, 1970,and 1991 areshown in Table 1. Medical history of hypertension, ischemicheart disease, diabetes mellitus, and body mass index (BMI; inkg/rn2) were controlled for. Multivariate analysis for the effectof time on cholesterol concentrations indicated significantchanges in total serum cholesterol concentrations (P