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Indian Journal of Community Medicine

Isolated Systolic Hypertension among Office Workers in North Indian Town

Author(s): A. K. Gupta, P. C. Negi, B. P. Gupta, A. Bhardwaj, B. Sharma

Vol. 31, No. 2 (2006-04 - 2006-06)

Introduction

Isolated systolic hypertension(ISH) has been identified as an entity since long1. About 20% of the elderly suffer from ISH2. ISH leads to three fold risk of cardiovascular accidents, and 2:2 fold rise in risk of myocardial infarction2. Recent evidence that treating ISH leads to a lowering of cardiovascular morbidity and mortality has aroused keen interest in this entity1. There is paucity of reliable estimates of burden of disease and distribution of cardiovascular risk factors. Disagregated data an burden of disease and risk factors in the community is required for the prevention of cardiovascular disease. Epidemiological studies, provide scientific foundation for such an approach by quantifying the potential value of treating and preventing high blood pressure in a population3. Previously, studies on ISH have been done in elderly. This study was done to determine the risk factors distribution and epidemiology of ISH in the employees working in various organized sector in Shimla.

Material and Methods

Shimla is a hilly town with a population of 1,10,360 situated at 31.06N and 77.13E.The organized sector was arbitrarily classified in 6 categories of the speculations of difference in nature of job and different administrative setup as academic institutions, central institutions, state organizations, public sector, private sector and autonomous bodies.

Numbers of institutions were selected in such a way so as to cover 1/3 of target population. All employees within selected institute were screened. Thus a sample of 7630 subjects was screened.

A mercury sphygmomanometer was used to measure blood pressure. After a 5 minute rest, blood pressure was initially checked by palpatory method. Then, BP was measured by auscultatory method, inflating the cuff to 30 mm above the level in a placatory method. This estimated auscultatory gap and also prevented cuff related rise in BP. The first and last Korotoff sounds were noted.

Two readings were taken after 5 minutes intervals and mean BP of the two reading was taken as BP of the individual. HT was confirmed by repeat readings after one week again by taking mean of two readings.

A pretested structured self-administered questionnaire to assess and quantify risk factors was used. This included age, sex, salt intake, alcohol consumption, smoking and physical activity. Alcohol was converted into ml of ethanol by formula5 (bottles of beer per month) x (12 oz) x (0.045 oz ethanol per oz beer) X (29.6 ml per/oz)/30 +(glasses of other alcoholic beverages per month) x (O.5 drink per glass) x (1.5oz) x (0.43 oz ethanol per oz sprit/s) x (29.6 ml per oz)/30. Smoking index6 was computed by multiplying the number of bidis/ cigarettes smoked per day by the number of smoking years. Dietary salt intake was calculated by monthly inventory recall method and divided by family members to get per capita consumption. Salt intake was divided in three categories, low salt intake ≥ 8g/day, moderate salt intake = 8 - 10g/day and high salt intake ≥10g/day. Physical activity index (PAI)8 was calculated by 24 hours recall method using weight age factor proportional to oxygen consumption. PAI score was divided into three categories. Mild physical activity = 24.0-28.9, moderate physical activity ≥ 29 - 36.9 and high physical activity = 37.0 - 83.0. Height and weight were recorded and body mass index (BMI) was calculated. Socio economic status was calculated according to Prasad's classification9. ISH was defined as systolic BP of 140 rnm of Hg or more and a diastolic BP of less than 90 mm of Hg. Awareness was defined as previous knowledge of hypertensive status. In the aware hypertensives, medications were not discontinued and BP measurements in these cases reflect the level of control of blood pressure attained.

Data was compiled and analyzed on MSTAT SOFTWARE (VER 4.0, Michigan State University, 1985).

Result and Discussion

The prevalence of ISH was 7.78%(7.96% in males and 6.7% in females). The prevalence in males is higher than previous study in Delhi (5.1%) but the prevalence in females is lower than the Delhi study (8.1 %). This sex difference may be due to low number of female in our study or simply difference of population studied. Our results are also higher than reported by Chou (6.1 %)10 and Garland (6%)11. These studies have used the old criteria of ISH as SBP > 160 with DBP < 90. So the difference in prevalence could be due to the lowering of the criteria for defining ISH and may be due to difference in population screened. Our results in age group > 50 are lower than studies in their elderly 16% in systolic hypertension in elderly programme and 17% in Stenberg study in epidemiology of Parkinsonism and hypertension in elderly. This was because we could not include subjects above 58 years of age, the retiring age of jobs. It is interesting to note that ISH is not confined to the elderly but also exists in young subjects <35 years of age. This aspect has not been previously highlighted. However our findings of high prevalence should be interpreted with caution, as in those cases under treatment it could not be determined whether these patients were on treatment of ISH or other forms of hypertension. The role of racial factors in explaining this high prevalence needs to be studied.

Table I: Life style risk factors in ISH

  ISH Total Prevalence(%)
Salt Intake
<8G/Day 142 2139 6.63
8-10G/Day 165 2148 7.68
>10G/Day 287 3343 8.59
PA1
24.0-29 114 481 23.7
29.0-36.9 457 6943 6.58
>37 33 206 11.16
Smoking
Non Smokers 381 5224 7.29
Smokers 213 2406 8.85
BMI
<18.5 57 808 7.05
18.6-24.9 391 5181 7.54
25-30 114 1375 8.29
>30 32 266 12.03
Alcohol
Non Drinkers   5336 7.76
0-10 ML/Day 141 1898 7.62
>10ML/Day 39 175 22.28

Mild (Stage I) ISH constituted most of cases. These cases will benefit by lifestyle modification. Of the lifestyle risk factors salt intake, Alcohol intake, Physical activity and body mass index were found to be significantly different in two groups(p < 0.001). Smoking index had wide standard deviation due to large number of non-smokers and heavy smoking pattern in those who smoked. Smoking was not a significant factor for ISH. A previous study in Taiwan has reported age, diabetes, blood urea nitrogen and physical activity as significant predictors of ISH. Salt intake was not investigated in this study while alcohol consumption was not quantified. So, this may have contributed to non significant relation of ISH to alcohol in Taiwan study. Our observation that ISH is largely asymptotic points to the hidden iceberg of disease. This may also explain the low (5%) awareness of ISH among our subjects. Annual health checkups should be mandatory for the employees in all offices and Client of health/life insurance.

References

  1. Memorandum from a WHO/ISH meeting, 1993 Guidelines for management of mild hypertension. Bulletin of World Health Organization 11993; 199371(5) 503-17.
  2. Chou P. Epidemiology of isolated systolic hypertension in Pu-Lui Taiwan. International Journal of Cardiology 1992; 35(2): 214-26.
  3. Joint National Committee on Detection, Evaluation and Treatment of high blood pressure. The Fifth Report of the National Committee on Detection, Evaluation and Treatment of high blood pressure 9JNC \/) Archives of internal medicine 1993; 153:154-82.
  4. Lawanga SK, TyeCY (ed) Teaching health stastics. Twenty lessons and seminar outlines. World Health Organization, Geneva 1986; 158-59.
  5. Croui MH. Alcohol consumption and blood pressure. Hypertention 1981;3 (5):557-65.
  6. Jindal SK, Malik SK, Dhand R. Bronchogenic carcinoma in northern India.Throx 1982; 37:343-47.
  7. Ghafoornissa K. Diet and heart disease. National institute of nutrition Hyderabad 1994:34-6.
  8. Kannel WB, Sorlies MS. Same health benefits of physical activity. The Framingham Heart Study Arch Intern Med. 1979;139:857-61.
  9. Kumar P. Social classification need for constant updating. IJCM 1993: XVII (2):60-1.
  10. Chou P, Chen CH, Chen HH. Epidemiology of ISH in Pu-Lui, Taiwan: Int J Cardiol 1992; 35(2):219-26.
  11. Garland C, Barrett-Connor E, Criqui MH. ISH and mortality after the age of 60 years. Prospective population based study. Am J Epidenniol 1983; 118:365-76.

Deptt. of Community Medicine,
Deptt. of Cardiology and Deptt. of Medicine IGMC, Shimla.
E-mail: [email protected]
Received: 18.11.1998

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