Epeidemiological study on arterial blood pressure at the Yonsei urban community health project area
The death rate due to cardiovascular disease, that is closely related to the level of blood pressure, has shown a gradual increase and become the top of the leading causes of death throughout most of the world. In Korea, the death rate due to disease affecting the central nervous system has taken 3rd place among the leading causes of death from 1963 to 1966. Especially, in recent years, disease affecting the central nervous system has become the top of the leading causes of death in those over 45 years of age. But, there are only a few well designed epidemiological studies of blood pressure in Korea.
Therefore, a study on the general distribution of blood pressured in a population of community in Korea and on several factors that are related to blood pressure is meaningful and important for solving the problems due to cardiovascular and
cerebrovascular diseases in Korea.
The specific aims of this study were as follows:
1) To know the general distribution of blood pressure by sex and age in the community.
2) To determine the relationship between the blood pressure level and selected
social factors, such as education, occupation, religion and social strata.
3) To determine the relationship between the blood pressure level and selected demographic factors, such as frequency of migration ,the number of children, the number of brothers and sisters, the number of pregnancies, and the birth order.
4) To determine the relationship between the blood pressure level and selected biomedical factors, such as weight, weight/height, weight/height**2, ponderal index and arm circumference.
5) To know the prevalence rate of hypertension.
6) To utilize the distribution of blood pressure levels, determined among a randomly selected sample of the adult population of the community, as a baseline for future epidemiologic studies.
7) To test the two hypothesises;
a) The crude relationship between the amount of salt intake and thye level of blood pressure,
b) A concordance between the level of blood pressure of husband and wife living together in the same household.
The community selected was Yonsei Urban Community Health Project Area with 7,000 households or about 38,000 residents.
This community is characterized by complexity in terms of various socio-economic factors. That is, this area is composed of 4 evenly devided socially characteristic strata: upper, middle, and low class, and slum population.
Households were the sampling unit. The sampling method applied to this study was a cluster, stratified and systemetic sampling with a random start using household registration list. Using the above sampling method 939 households from the total 7,000 households were selected. There were 2,053 residents of age 20 years and over in these 939 households.
10 senior nursing school students were employes as interviewers. They were trained by one doctor of internal medicine, for the technic on measurement of blood pressure, and by two doctors of preventive medicine, for the technic on interviewing and filling out the questionnaire. After 7 days of training, the inter-observer variation and digit preference were eliminated and they started filed work for about two months from September 1, 1971.
Of the 939 households. 98.4% were visited, and 92.5% of the sample population were checked for blood pressure and interviewed.
The number of blood pressure measurement on each person was 3 times with 5 minutes intervals. The collected data was analyzed with an Olivetti Underwood programma 101 computer.
The outstanding findings of this study were as follows:
1) Both mean systolic and diastolic blood pressure were higher among males than that of females through all age groups.
2) For both sexes, mean systolic and diastolic blood pressures increased by the progress of age.
3) The proportion of the population with hypertension(over 160/95 mmHg) increased with age and there were less women than men who were classified as hypertension.
4) High mean systolic and diastolic blood pressures tended to be associated with low educational level and social stratum, but there were no differences by occupation and religion.
5) For both sexes, the mean systolic and diastolic blood pressures in those from rural backgrounds were higher than in those from urban backgrounds in the young age groups, but in the old ages, the reverse was found.
6) The relationship between the level of blood pressure and several biomedical factors, such as weight, weight/height, weight/height**2, ponderal index and arm circumference showed high positive intercorrelation.
7) For males, current smokers tended to have higher mean blood pressure than those who never smoked, through almost all age groups, and heavy drinkers tended to show higher mean blood pressure than moderated drinkers in young age groups, but in
old age groups no difference was found.
8) For both sexes, people with hypertension histories in their family, tended to show higher mean blood pressure level.
9) For both sexes, heavy salt intakers tended to show higher mean blood pressure than low salt intakers in young age groups.
10) In terms of couple concordance, diastolic blood pressure showed positive correlation(correlation coefficient; 0.436) in those 40 years of age and over.