Introduction: CVD is the most important cause of death all over the world. The burgeoning burden of CAD in India can be explained by the rise in prevalence of risk factors like diabetes, hypertension, dyslipidemia, smoking, obesity, physical inactivity & urbanization. The aim of the study is to compare the risk factors of patients with CAD& their siblings. Method: It was a case-control study, conducted over a period of 1.5 years. In this study CAD patients and their siblings without CAD; age <60 years were included. Both groups were compared for CAD risk factors. Results: Total 100 patients their 100 siblings were taken. Patients were more smoker(19% patients &4% siblings p =0.001), more heavy alcohol consumption(21% patients &10% siblings p = 0.032), more moderate and high stress level(56% patients & 38 % siblings p= 0.037), more physical inactivity(70% patients &51% sibling p=0.019), more central obese(abnormal WHR for male 41% patients &25% siblings p= 0.024 and for female 21% patients &16% siblings p= 0.037), more hypertensive(40% patients & 22% siblings p=0.003), more diabetic(44% patients &11% sibling p=0.000), more intake of carbohydrate(p= 0.014), & fats(p= 0.033) and low HDL cholesterol(69% patients &46% siblings p= 0.001). Beside this among siblings’ prevalence of prehypertension, prediabetes and dyslipidemia were high. Conclusion: We found that CAD risk factors were high in patients compared to their siblings. Beside this among sibling prevalence of prehypertension, prediabetes and dyslipidemia were high. So, to prevent CAD these factors should be controlled.
Schemic heart disease (IHD) is a condition in which there is an inadequate supply of blood and oxygen to a portion of the myocardium; it typically occurs when there is an imbalance between myocardial oxygen supply and demand. The most common cause of myocardial ischemia is atherosclerotic disease of an epicardial coronary artery.[1]
Over the past decade, cardiovascular disease (CVD) has emerged as the single most important cause of death worldwide. In 2010, CVD caused an estimated 16 million deaths and led to 293 million disability-adjusted life-years (DALYs) lost—accounting for approximately 30% of all deaths and 11% of all DALYs lost that year. Like many high-income countries (HICs) during the past century, now low- and middle-income countries (LMICs) are seeing an alarming and accelerating increase in CVD rates.[2] Epidemiologic studies from various parts of India indicate a prevalence of CAD to be between 7% and 13% in urban [3-5] and 2% and 7% in rural. [6-7]
The burgeoning burden of CAD in India can be explained by the alarming rise in the prevalence of coronary risk factors like diabetes, hypertension, atherogenic dyslipidemia, smoking, central obesity and physical inactivity. Rapid urbanization and change in lifestyle that occurred during the past two decades have led to the growing burden of coronary risk factors in India.[8]The risk of CAD in Indians is 3-4 times higher than White Americans, 6-times higher than Chinese, and 20-times higher than Japanese.[9,10] Indians are prone as a community to CAD at a much younger age.[11,12]The CAD risk factors are classified as non-modifiable (e.g.: sex, age, genetics and positive family history) and modifiable behavioural factors (e.g.: diet, physical inactivity, smoking, alcohol consumption); biological factors (e.g.:dyslipidemia, diabetes, hypertension, obesity) and finally societal factors, which include a complex mixture of interacting socio-economic, cultural and other environmental [13]
Due to several genetic and environmental factors population, first degree relatives of patients with coronary heart disease have a significant higher risk of getting cardiovascular events. This excessive risk is due to interplay between genetic as well as environmental factors. Clustering of various risk factors such as eating and life style habits, socio-economic status, exercise pattern and disease process like dyslipidaemia, hypertension, defects in glucose metabolism make family members more prone to similar non- communicable diseases.[14]In this study we want to compare distribution of risk factors (behavioural, physical and bio-chemical) among first-degree relatives of patients with a known CAD. So the central concept of preventive cardiology can be fulfilled, that is early identification of CAD risk factors and treatment of the associated risk will result in improved survival as many risk factors begin accumulating at a young age, often while individuals are asymptomatic.
This case-control study was conducted in Dayanand Medical College and Hospital, Ludhiana (Punjab), India; among the patients with coronary heart disease and their sibling over a period of 1½ years.
Inclusion criteria
Exclusion criteria
Procedure
After Informed consent from both patients and siblings, detailed history including history of hypertension, diabetes mellitus, dyslipidemia, smoking, and alcohol intake was taken. Quantification of smoking was done with the smoking index (SI). It was defined as the number of cigarettes/bidis smoked per day multiplied by the number of years smoked. [15,16] Based upon SI, patients were categorized into the following groups:
I : Never smokers
IIa : Light smokers [SI = 1 to 100]
IIb : Moderate smokers [SI = 101 to 300]
III : Heavy smokers [SI = >300]
Quantification of Alcohol consumption was done by a questionnaire. Total alcohol intake was computed in gm /day and the amount of the alcohol content in different type of beverages calculated as 360 ml (12 ounces) of beer contains 13.2 g of ethanol; 11.3 g of ethanol for 360 ml (12 ounces) of light beer; 10.8 g of ethanol for 120 ml (4 ounces) of wine; and 15.1 g of ethanol for 45ml (1.5 ounces) of liquor (gin, bourbon, whiskey, vodka, liqueurs).[17] Habitual heavy alcohol consumption, defined as 8 or more drinks per week for women and 15 or more drinks a week for men.[18]
Socio-economic status was defined on basis of Kuppuswamy’s Scale (2016). Socio-economic classes.[19]
Score Socio-economic class
Level of Physical Activity was measured as per groups suggested by Dewan et al[20]
Personal stress was measured on basis of Perceived Stress Scale Score [21] Grading of stress
- 0-13 Low stress
- 14-26 Moderate stress
- 27-40 High perceived stress
Food frequency questionnaire was used to assess the nutritional status of both patients and their siblings using Indian food composition tables 2017.[22]
Clinical examination along with anthropometric evaluation was carried out including Height, weight, waist-hip ratio i.e. waist circumference/ Hip circumference (waist circumference measured between lower limit of rib cage and the iliac crest in centimeters with subject standing using flexible non distensible tape and Hip circumference measured around the widest portion of the buttocks, with the tape parallel to the floor) and , BMI (was calculated by formula - body weight (in kilogram) / height2 (in meter). Any abnormality in these parameters defined by as per WHO guideline.[23] Blood pressure measurement was done after 10 minutes rest in supine position, with no tight clothes, mean of two measurements was registered and hypertension defined by JNC 7 criteria.[24] Laboratory investigations were done including CBC, RFT, FBS, Lipid Profile, 12 leads ECG, and TMT /2D ECHO.
Statistical Analysis
Results were expressed as mean ± SD for continuous variables or percentages for categorical data. Appropriate descriptive statistical methods were applied to analyze the results. P < 0.05 would be considered as statistically significant.
A total of 100 patients & 100 siblingswere taken and compared with each other. Baseline characteristic showed (table 1) mean age 48.957.75 for patients and 47.068.62 for siblings. In patients’ group 70 male/30 female and in siblings’ group 64 male /36 female were present. We found that in 72 % patients and 68% siblings were urban whereas 28% patients and 32% siblings were rural with p value of 0.644. In patient group 68% patients and 60% siblings had nuclear whereas 32% patients and 40% siblings had joint family type with p value of 0.239. Patients were more smoker (19% patients and 4% siblings p =0.001), more habitual heavy alcohol consumption (21% patients and 10% siblings p = 0.032), more moderate and high stress level (56% patients and 38 % siblings p= 0.037), more physical inactivity (70% patients and 51% sibling p=0.019) more central obese (abnormal WHR for male 41 patients and 25 siblings p= 0.024and for female 21 patients and 16 siblings p= 0.037). In this study patients were more hypertensive (40% patients and 22% siblings p=0.003), more diabetes (44% patients and 11% sibling p=0.000, more dietary carbohydrate (430.92 gm/day for patients and 409.18 gm/day for sibling p= 0.014), more dietary total fats ( 83.42 gm/day for patients and 79.99 gm/day for sibling p= 0.033) and low HDL cholesterol (69% patients and 46% siblings p= 0.001) (fig 1). Beside this siblings group prevalence of prehypertension (36% patients and 31% their sibling), prediabetes (26% patients and 32 % sibling) and dyslipidemia (mean LDL 100.69±38.02 in patients and 120.56±29.01 in sibling )are also high(fig 2).
Table 1
Characteristic |
Patients (n=100) |
Siblings (n=100) |
P value |
Age (mean) |
48.95±7.75 |
47.06±8.62 |
- |
Sex (male/female) |
70/30 |
64/36 |
- |
Family type(joint/nuclear) |
32/68 |
40/60 |
0.239 |
Residence (urban/rural) |
72/28 |
68/32 |
0.644 |
Socioeconomic status (means KSS) |
17.87±6.05 |
17.84±6.05 |
0.897 |
Smokers |
19 |
4 |
0.001 |
Habitual heavy alcoholic intake |
21 |
10 |
0.032 |
Perceived stress scale score (mean) |
18.76±8.41 |
14.75±7.59 |
0.037 |
physical inactivity |
70 |
51 |
0.019 |
BMI (mean kg/m2) |
27.60±4.45 |
27.07±4.01 |
0.508 |
WHR (mean male/female) |
0.93/0.90 |
0.91/0.86 |
0.024/0.037 |
SBP/DBP (mean, mm of hg) |
127.26/77.93 |
123.96/75.22 |
0.003 |
FBS (mean, mg/dl) |
140.77±66.70 |
106.47±33.05 |
0.000 |
Diet Carbohydrate (mean, gm/dl) Total Fat (mean, gm/dl) Protein (mean, gm/dl) Total Calories (mean, gm/dl) |
430.92±64.92 83.42±33.70 97.38±20.01 2458.31±374.97 |
409.18±59.16 74.99±20.12 98.45±23.66 2392.54±353.05 |
0.014 0.033 0.730 0.203 |
Lipid profile Total Cholesterol (mean, mg/dl) Triglyceride (mean, mg/dl) HDL Cholesterol (mean, mg/dl) LDL Cholesterol (mean, mg/dl) |
172.60±48.63 153.74±65.96 35.83±8.95 100.69±38.02 |
181.61±32.93 139.89±68.52 42.64±11.19 120.56±29.01 |
0.209 0.284 0.001 0.000 |
Non-communicable diseases like cardiovascular disorders, cancerand diabetes constitute 68% of global death annually. Among this 40% of deaths were in the age group of 30 to 70 years. CVDs alone constitute 31% of global deaths making it the leading cause of death. Meanwhile, in India, non-communicable diseases account for 60% of all deaths and cardiovascular diseases alone contributes to 26 % of Indian mortality. Across the globe also peak has shifted from developed to developing countries. [25-6] In our study, we are comparing the risk factors of CAD between patients and their siblings. Because genetic background between these two groups are almost the same so we can find out where genetic or environment play a role for the disease.
In India, studies have stated increasing coronary heart disease prevalence over the last 60 years, from 1% to 9%-10% in urban populations and <1% to 4%-6% in rural populations. [27-8] In our study,although CAD more in who were urban compared to rural but type of residence was not statistically significant. Furthermore, other studies in rural areas have indicated a lower prevalence of CAD compared to urban areas, however, an increasing trend is seen among them as well.[29,30]
In this study, nuclear family more common in both patient and sibling group but it doesn’t mean person with nuclear family had risk of CAD because when we compared patients with their siblings for family type it was found that family type was not statistically significant. Similar results found in a study done by Lofti MH et al in which family type is not statistically significant.[31]
In our study smoking was found in 19% of patients and 4% siblings. When comparison was done for smoking in both it was very significant that mean smoking is very important and preventable risk factor for CAD. This finding was lent support by Rahman et al[32] Rastogi et al[33]; the INTERHEART study[34]; and McKeigue et al.[35] But in our study low incidence of smoking was found compared to the above studies because the study was done in Punjab where most of the person follow Sikhism in which smoking is prohibited.
The present study showed that habitual heavy alcohol consumption was present in 21% patients and 10% siblings. When we compared both groups it was found that it was statistically significant. Rastogi et al[33] and Ram RV et al[36] had found a significant association for alcohol intake and CAD as in our study while the non-significant association was found in CUPS study[37] and Bagchi et al[38] This is because the relationship between alcohol intake and CAD represents a U-shaped curve, moderate alcohol consumption confers a lower risk of CVD compared to both heavy drinkers and non-drinkers.[18,39]
In developed countries, where the lower SES groups suffer higher CAD and deaths due to noncommunicable diseases.[40] These patterns may be related to enormous changes in dietary customs and living styles, increased awareness and education about risk factors.[36] But the results of our study showed that socioeconomic status comparable between patients and their siblings. Similarly, McKeigue and Marmot [41] found no difference in the prevalence of IHD among South Asians in Britain from different socioeconomic backgrounds. In our study stress level was very high in patients. This finding is supported study done by Deshpande JE et al[42] and INTERHEART study.[34]
The WHR is a measure of abdominal obesity and a surrogate measure for visceral fat deposition.[43] Current clinical guidelines using BMI to define overweight and obesity may miss identification of a person at “normal” BMI levels with increased cardiovascular disease risk related to central fat distribution. We found differences between BMI and WHR in associations with CVD. On comparison of these anthropometric data between patients and siblings group it was found that only WHR is statistically significant, not BMI. Our finding is supported by studies done by Gelber RP et al[44] and Dalton M et al.[45] Besides this Waist-hip ratio was established as a significant risk factor in studies conducted by Rastogi et al.[33] and in INTERHEART study.[34]
Physical inactivity has become a leading risk factor for CVD globally. Asian Indians, in general, are less likely to exercise in comparison to the white population. This sedentary lifestyle promotes obesity.[46] In our study light physical activity was present more in patients than siblings. Similar finding found in a study done by Deshpande et al[42], Ram et al[36] and INTERHEART study.[34]
Review of literature shows that hypertension has been significantly associated with cases of CAD or ACS in various studies conducted by Rastogi et al. [33] INTERHEART study [34] Ram et al. [36]and CUPS study [36]as in our study. Prehypertension it was found in 36% patients and 31% siblings so it means that siblings prone to develop hypertension as well as CAD, later on, some genetic link should be there. McCaffery JM et al [47] conducted a twin study and found that certain lifestyle factors (especially, alcohol consumption, physical inactivity, and a high-calorie diet) may contribute to common aetiological variance among risk factors like blood pressure, body mass, and lipids.
Diabetes Miletus is considered as “Coronary Heart Disease Equivalent”.[45] this study finds a statistically significant association between diabetes and CAD between patients and their sibling. In CREATE registry 30.4% of patients had diabetes among patients of ACS.[48] OASIS 1 and 2 registries reported 39.1% of all ACS patients from India were diabetic.[49] While other studies conducted by researchers like Babu et al [50], and INTERHEART study [34] also found similar findings. Similar to prehypertension, impaired fasting sugar was present in 26% patients and 32 % sibling that means siblings are prone to develop diabetes as well as CAD in future.
Waingankar PJ et al [51] and Pawar RB et al [52] found in their studies that CAD patients had more fat and total calories intake compare to their control. In our study, it was found that it was fats and carbohydrate intake was statistically significant but for protein and total calories intake were statistically insignificant between patients and their siblings. It means that in patients group carbohydrate and fat is the main source of total calories compared to their siblings that may make them prone to develop CAD. Sugiri et al[53] found in this study that a high carbohydrate intake could pose a risk factor for the significant CAD in young but Dehghan M et al in the PURE study found that higher carbohydrate intake was associated with an increased risk of total mortality (but not with the risk of cardiovascular disease or cardiovascular disease mortality.[54]
Lipid abnormalities are a widely accepted risk factor for IHD. Studies on Indian populations in other countries have reported that Indians compare to white or Afro-Caribbean populationshave lower HDL cholesterol and higher triglyceride concentrations.[55] In our study, although the mean HDL cholesterol was low in patients and it is statistically significant but mean triglycerides were high and mean total cholesterol and mean LDL was low in patients compared to their siblings. Both TG and total cholesterol were statistically insignificant but in LDL cholesterol statistically significant for siblings. This variation in findings can be explained by the fact that most of our study patients had AMI itself ,high dose statin and use of heparin. Another reason may be a genetic linkage between patients and sibling. Similarly, a study done by Pais et al[57] in survivors of acute myocardial infarction (AMI) showed no association of lipid abnormalities with CAD.
This case-control study compared risk factors in patients with CAD vs their siblings without CAD. The pertinent conclusions drawn are:
To conclude, we found that socio-behavioral habits like smoking & alcoholism, high level of stress, dietary habits, physical inactivity, central obesity, hypertension, diabetes, high intake of carbohydrate and total fats and low HDL cholesterol are considerably high in CAD patient compared to their healthy sibling. Besides in siblings prevalence of prehypertension, prediabetes and dyslipidemia is also high. It is important to identify and control these risk factors so as to prevent CAD.