You are here

Article Text

Article menu

Download PDFPDF

Original research
Angina in primary care in Goa, India: sex differences and associated risk factors
Free
  1. Irwin Nazareth1,
  2. Gladstone D'Costa2,
  3. Eleftheria Kalaitzaki1,
  4. Raj Vaidya2,
  5. Michael King3
  1. 1Medical Research Council, General Practice Research Framework & Research Department of Primary Care & Population Sciences, University College London Medical School, London, UK
  2. 2Voluntary Health Association of Goa, Panjim, Goa, India
  3. 3Research Department of Mental Health Sciences, University College London Medical School, London, UK
  1. Correspondence to Professor I Nazareth, Department of Primary Care & Population Sciences, University College London Hampstead Campus, Rowland Hill Street, London NW3 2PF, UK; i.nazareth{at}ucl.ac.uk

Abstract

Background Little is known about the prevalence of angina in people seen in Indian general practices. The authors assessed the prevalence of angina and its associated risk factors in Goan general practices.

Methods Cross-sectional study on consecutive attendees in nine private general practices in Goa, India. All participants completed the Rose Angina Questionnaire, to ascertain the presence of angina. Other demographic, clinical and biochemical data were also collected.

Results 1556 (626 men and 930 women) consecutive attendees aged 30 to 75 years. Angina was detected in 37 (5.9%, 95% CI 2.4 to 9.4%) men and 99 (10.6%, 95% CI=7.4 to 11.2%) women. The prevalence of angina increased with age in both sexes but was greater in women between aged 46–60 (OR=4.3 (95% CI 2.0 to 9.2)) when compared with men. When compared with men, the odds of angina in women of all ages was 2.03 (95% CI 1.10 to 3.75) after controlling for confounders. Angina was associated with depressive and/or anxiety symptoms in both sexes (men OR=5.65, 95% CI=2.25 to 14.16; women OR=2.18, 95% CI=1.01 to 4.69) and with hypertension in men (OR=3.82, 95% CI=1.57 to 9.30) and family history of coronary heart disease (OR=1.53, 95% CI 1.05 to 2.24) in women. Borderline/high total cholesterol levels (OR=0.5, 95% CI 0.28 to 0.89) in women were associated with a reduced risk of angina.

Conclusion Women attending general practices in Goa, India are at greater risk of angina than men. Depression/anxiety is strongly associated with angina. Greater awareness of the general practitioners to the disparity in angina between the sexes and its association with psychological distress is required.

  • Angina
  • depression
  • anxiety
  • general practice
  • India

https://doi.org/10.1136/ha.2009.001255

Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

    Introduction

    Mortalities from coronary heart disease (CHD) in India range from 75 to 100 per 100 000 people in the sub-Himalayan states of Nagaland, Meghalaya, Himachal Pradesh and Sikkim to 340–430/100 000 in Andhra Pradesh, Tamil Nadu, Punjab and Goa, with the highest rates in Goa.1 The community prevalence of CHD in urban Tamil Nadu increased from 35/1000 in men and 45/1000 in women2 to 62/1000 in men and 93/1000 in women3 from 1994 to 2001, but its prevalence among those seen in general practice in India is unknown.4

    South Asian women are at greatest risk of CHD; nine of the 12 studies from urban India and six of nine from rural India reported higher rates in women than in men.4 Data from two of three population-based studies that compared South Asians with white British people reported higher rates for CHD (ie, angina and MI) in South Asian women than men,5–7 whereas white women had lower rates than white men in all three studies.6–8 These studies, however, were limited by the lack of standardised assessments of angina.6 8–10

    Little is known about the prevalence of angina in general practice attendees in India. Our objective was to compare rates of angina in men and women attending general practices in Goa and to examine the association of angina with known risk factors.

    Method

    Goa is India's smallest, but richest per capita, state in India, with a population of 1.3 million people. For approximately 450 years from the 16th century until 1961, when it became a part of India, it was governed directly from Portugal. It currently enjoys a reputation as the busiest Indian tourist destination.

    Ten family practices across Goa who expressed an interest in research were approached. All were single-handed and included urban and rural private practitioners serving people from a spectrum of socio-economic circumstances. Although there is a government system of free public health, there are no publicly funded family practices in India. Primary medical care is provided through a combination of private general practices and government-funded public health services. At least 80% of people in India use private medical services as their first point of contact.11 12

    The Independent Ethics Committee in Mumbai approved this study conducted in private general practices.

    Recruitment of practices and participants

    We recruited private general practices that had at least 20 patients consulting daily and room space to run the study. Participating doctors were briefed on the research protocol. All researchers were trained on study procedures by IN and MK with support from GD and RV.

    Consecutive attendees (which included new and regular patients) aged 30 to 75 were approached and given a study information sheet. This was read out and explained to illiterate participants. We excluded pregnant women and those judged by the researcher and/or the doctor to be too unwell to participate. The study was conducted from April 2004 to January 2005. Those consenting provided information on the following.

    Demography

    Age, sex, birth place, religion, education, monthly income and details of current housing

    Clinical measures of angina

    1. The World Health Organization's Rose Angina Questionnaire provided a definite (Rose Questionnaire Definite or RQD) or possible diagnosis of angina (Rose Questionnaire Possible or RQP).13 Cross-sectional studies have shown that those positive on the Rose Angina Questionnaire have more risk factors, resting ECG abnormalities, carotid intimal thickness14 and coronary artery calcification.15 In South Asians, the capacity of the RQP to identify those reporting a doctor's diagnosis of angina (sensitivity) and those who reported no diagnosis (specificity) was 0.81 and 0.87, respectively, in men and 0.74 and 0.81 in women. These values were considerably lower for the RQD with the sensitivity and specificity at 0.21 and 0.97, respectively, in men and 0.08 and 0.96 in women.16

    2. Past history of angina, hypertension or diabetes was recorded using questions from the Health Survey for England.17

    3. A history of CHD in either parent or sibling was recorded using a standardised questionnaire.18

    Known risk factors for CHD

    1. Waist and hip sizes were measured in order to calculate the waist/hip ratio, and values greater than 0.95 in men and 0.8 in women were classified as abnormal.19

    2. Participants with a self-reported history of hypertension and/or those with a blood pressure greater than 140 mm of Hg systolic or 90 mm of Hg diastolic on assessment were categorised as hypertensive.

    3. Past or current use of tobacco (cigarettes, beedis (unfiltered cigarettes rolled in dried tobacco leaves), cigars and chewing tobacco) was recorded using modified questions derived from the Health Survey of Engalnd.17

    4. Alcohol use was recorded as abstention or consumption.

    5. We defined significant physical activity over the previous month as participation in at least one of the following activities: (i) brisk walking for at least 20 min three times a week; (ii) intensive physical activity at work (eg, digging, clearing rough ground, stone or bricklaying); or (iii) heavy household work (eg, spring cleaning, walking with heavy shopping). This was also derived from the Health Survey of England.17

    6. Psychological distress was assessed using the K10, a WHO-validated screening instrument.20 Moderate and high risk are defined as total scores greater than 6 and 9, respectively, out of a maximum possible score of 40.20 This questionnaire has been tested in a Goan general practice population and against ICD 10 criteria for depression and anxiety. K10 was found to be highly sensitive and specific with an estimated area under the curve of 0.8774.21

    Serological risk factors for CHD

    Participants provided fasting blood samples collected 2–3 days after interview. These were delivered on the same day to a central laboratory for analysis using a SLIM (SEAC) semiauto-analyser. We estimated serum total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride and blood glucose, and classified the results accordingly:

    1. Diabetes: based on the National Heart, Lung and Blood Institute of the USA (http://www.nhlbi.nih.gov/) that classifies fasting blood glucose of under 100 mg/dl as normal; 100–125 mg/dl prediabetic and over 125 mg/dl diabetic. People giving a history of diabetes and/or those with a fasting glucose over 125 mg/dl were categorised as diabetic.

    2. Elevated serum lipid levels: based on the National Heart, Lung and Blood Institute recommendations of serum cholesterol (high ≥240 mg/dl, borderline 200–239 mg/dl), HDL (low ≤40 mg/dl in men and ≤50 mg/dl in women), LDL (high ≥160 mg/dl, borderline 130–159 mg/dl), triglycerides (high ≥150 mg/dl) and the ratio of total cholesterol to HDL ≤4 as a normal level in both sexes.

    Sample size estimation

    The prevalence of angina in this population is not known. However, using a conservative estimate of a prevalence of 5% in men, if we were to demonstrate a higher prevalence of 7.5% in women at 90% power and 5% significance, we would need to recruit 620 men and women to the study.

    Analysis

    All statistical analyses were conducted using Stata Release 9.1 (Stata, College Station, Texas).22 We used Stata Survey commands to adjust for clustering within general practices. We tested the independence of categorical factors using the Pearson χ2 statistic corrected by the second-order Rao–Scott correction23 24 to produce an F statistic and adjusted Wald tests for continuous normally distributed factors such as age. We compared responses in men and women to individual questions of the Rose Angina Questionnaire for possible (RQP) and definite (RQD) criteria, to evaluate whether there were any significantly different symptoms profiles between the sexes. We calculated age-standardised rates of angina in men and women using the age bands 30–45, 46–60 and 61–75 of the Goa Census data.25

    Multivariable analyses

    We identified identify clinical and serological risk factors associated with angina and sex (ie, being male of female) at or below a p value of 0.1. These were fitted a final model for men and women separately. Using a stepwise deletion based on α of 0.1, we then identified the final set of variables most strongly associated with angina.

    Results

    Response rates

    Nine of the 10 practices approached participated. Only four people were judged to be too ill to take part on account of advanced terminal illnesses. We approached 1556 (626 men and 930 women) general practice attendees, and all of those approached agreed to participate. The offer of a free blood test served as a strong incentive to participate. There were sex differences in literacy, educational qualifications, employment, family annual income, religious denomination (table 1), waist–hip measurements, blood glucose, HDL, LDL and triglyceride levels, use of tobacco and alcohol, depressive and/or anxiety symptoms, and family history of CHD between men and women (table 2).

    View this table:
    Table 1

    Demographic details of study sample

    View this table:
    Table 2

    Coronary heart disease risk factor details of study sample

    Prevalence of angina and demographic factors

    In both sexes, the prevalence of angina increased with age with variable estimates in the nine practices (range: men=2.2 to 12.5%; women=4.9 to 20.3%). Women were at greater risk than men at all ages, but this was significant in the age group 46–60 (table 3). Highest qualification and annual family income were identified as possible confounders (ie, these were associated with both having angina and being male or female at the 0.1 level). After adjustment for these two factors, angina remained significantly higher in women (OR=2.03, 95% CI=1.10 to 3.75).

    View this table:
    Table 3

    Prevalence of coronary heart disease: age and sex breakdown

    Of the people identified with angina, only one woman and three men had a previous history of a myocardial infract, and only one man reported a prior history of stroke.

    Demographic and CHD risk factors associated with angina

    On univariate analyses in women, angina was associated with living alone, religious group, borderline or high total cholesterol levels and depressive and/or anxiety symptoms. In men, it was associated with home ownership, satisfaction with their living arrangements, not being born in Goa, elevated blood pressure and risk of depression and anxiety disorder (table 4 & 5).

    View this table:
    Table 4

    Univariate association of demographic factors with prevalence of angina

    View this table:
    Table 5

    Univariate association of coronary heart disease risk factors with prevalence of angina

    On multivariable analysis in women, angina was more likely to be associated with a family history of CHD and risk of depression and anxiety disorders, and less likely to be associated with borderline or high cholesterol levels. In men, it was associated with elevated blood pressure and symptoms of depression and/or anxiety (table 6).

    View this table:
    Table 6

    Multivariable models of associations of Coronary heart disease risk factors for men and women separately adjusted for age

    There were, however, a large number of participants (229, 15%) who were unable to provide information on their family history of CHD. It is very likely that these data were missing at random. On further inspection of the data missing on this variable, we did not find any demographic difference between the people with missing information and the rest of our sample. Nevertheless, since 15% of the information on family history of CHD was missing, we ran the multivariable analyses once again without this variable. This led to minimal changes to our findings. In addition to the rest of the variables in table 6 which were retained in the model, borderline or high levels of triglycerides (OR 1.70, 1.07 to 2.69) became directly associated with angina in women, and a weak association between angina and drinking alcohol (OR 1.72, 0.94 to 3.17) was found in men.

    We conducted a search for relevant interactions between the variables associated with angina on multivariable analyses in men and women. In women, there were no significant interactions, but in men, we observed an interaction between high blood pressure and symptoms of depression and/or anxiety (p=0.045). Thus, a further analysis was done separately on men who had symptoms of depression and/or anxiety but no high blood pressure and men with both, high blood pressure and the presence of depressive and/or anxiety symptoms. We found a non-significant trend for angina (OR=2.1, 95% CI 0.42 to 11) in the former group and a strong association with angina (OR=20, 95% CI=7.8 to 53) in the latter group.

    Pattern of responses to the Rose Angina Questionnaire

    Given the unexpected elevated prevalence of angina in women as well as its direct association with psychological symptoms but inverse association with serum cholesterol, we compared men and women on distribution of responses with individual questions of the Rose Angina Questionnaire. The only significant differences between men and women were as follows. Women with RQP were more likely than men to indicate the typical angina area for the pain (question 2—women 90%, men 50%, χ2=9.34, p=0.002). There was however a trend for these women to be less likely than men to agree that the pain subsided on rest (question 6—women 82%, men 100%, χ2=2.87, p=0.09). There were no differences in the pattern of responses between men and women with RQD.

    Discussion

    Main findings

    Ten per cent of women and almost 5% of men aged 30 to 75 attending general practices in Goa have angina. Women aged 46–60 were at greater risk than men. After adjusting for demographic confounders, the odds of angina in women of all ages were twice that in men. Psychological distress was strongly associated with angina in both men and women. Additionally, hypertension with psychological distress was strongly associated with angina in men. Borderline and high total cholesterol levels in women were associated with a lower prevalence of angina.

    CHD in India

    The burden of CHD is rising in India with an estimated prevalence of 3–4% in rural areas and 8–10% in urban areas,26 representing a twofold and sixfold rise in rural and urban areas, respectively, over the past four decades. India has the largest number of people with diabetes in the world with a rise in type II diabetes from less than 3% in 1970 to 12% in 2000.27 This increase in morbidity from diabetes and CHD may be due to the changes in lifestyle and diet that come with economic prosperity. Goa is the richest state in India and has the highest CHD mortalities in the country.1 Further research on whether case finding by the general practitioner in Goa, India could enhance early detection and effective management of the condition is nescssary.

    Angina in Indian women

    CHD is the commonest cause of death in women across all countries throughout the world.28 Although men are more likely to suffer non-fatal myocardial infarctions,29 population research indicates that the prevalence of chronic stable angina in some countries may be similar in men and women.30 31 Recent evidence from a systematic review, however, suggests that the prevalence of angina showed a small female excess of 20%.32 This female excess was found across countries with widely differing myocardial infarction mortalities in women. Moreover, it was found to be higher in non-Caucasian ethnic groups than in Caucasians. The female excess of angina in our study, however, exceeds that which has previously observed.

    General practice data from 98 general practitioners in Sydney estimated an angina prevalence rate of 6.5% in men and 3.5% in women.33 Recent data from the UK derived from 8970 practices and 55.5 million people reported CHD prevalence rates of 3.7% with wide variation between practices (0–34.6%).34 There were no data on angina in this study. Moreover, there are no published statistics from Indian general practice.

    In men, angina was associated with psychological distress and high blood pressure. In women, it was also related to higher levels of psychological distress but raised cholesterol levels were associated with a reduced risk of angina. This might suggest an atypical picture of cardiac pain which may be psychological in origin.33 However, at least two findings go against this possibility. First, there was an even stronger association between psychological distress and angina in men, and second, there were no important differences between men and women in their responses to the Rose Angina Questionnaire. Men and women classified with the Rose Angina Questionnaire (RQP and RQD) had very similar responses to the key angina questions. However, it is difficult to explain the lower prevalence of angina in women with borderline or high cholesterol levels. This study was a cross-sectional study and not designed to explain mechanisms of angina occurrence, and hence this finding requires further investigation.

    Psychological distress

    Emotional distress was associated with angina in both sexes. In men, the combination of psychological distress and an elevated blood pressure increased the risk of angina. Depression and anxiety disorders affect heart rhythms, increase blood pressure and alter blood clotting due to increased platelet aggregation.35 They can also lead to elevated insulin and cholesterol levels. Furthermore, depression or anxiety leads to chronically elevated levels of stress hormones, such as cortisol and epinephrine36 so that the body's metabolism is diverted away from the type of tissue repair needed in heart disease. Alteration in the ratio between sympathetic and parasympathetic tone makes people with depression more susceptible to arrhythmias by lowering the threshold for ventricular fibrillation.37 38

    Recent data from 755 Australian women aged 23–97 suggested that lifetime depression is strongly associated with angina and somewhat less so with cigarette smoking but not at all with some of the other risk factors such as weight, cholesterol levels, hypertension, inactivity and diabetes.39

    Depression often goes undiagnosed and untreated. People with heart diseases, their families and friends, and even the family doctors and cardiologists may misinterpret symptoms of palpitation, chest pain and breathlessness as accompaniments to heart disease rather than signs of depression and vice versa. General practitioners need to recognise symptoms of depression, enquire about their duration and severity, diagnose the disorder and recognise this as possibly being closely associated with CHD.

    Strengths and limitations of the study

    We could not find any other studies that assessed the prevalence of angina and CHD risk factors among general practice attendees in India. We chose a sample of private practices that served rural and urban communities with a range of socio-economic conditions in Goa and achieved 100% participation. The study practices opted to take part in this study and hence may not be represent private Goan general practice. There were demographic differences between the sexes. Women were more likely to be widowed, to have lower educational achievements and to be engaged in household-related occupations. This was with the exception of family income and religious denomination, in keeping with the socio-demographic difference generally observed between the sexes in this population under investigation.25 Our analysis adjusted for the demographic variables that confounded the association between angina and sex.

    Our estimate of the prevalence of angina was limited to a past history of the disease or existing angina based on the Rose Angina Questionnaire. We did not use other diagnostic criteria such as electrocardiography (ECG), as the accuracy of the Minnesota Code of ECG findings in epidemiological research has recently been contested.40 The Rose Angina Questionnaire remains the best known standardised instrument for assessing angina, and the RQP has been found to be an accurate assessment of angina in people from South Asia.14 We used a validated psychological assessment instrument.

    The study was limited by its cross-section nature, and hence our multivariable analysis was not able to ascertain a causal relationship between angina and the significant clinical and biochemical markers. Nevertheless, the elevated rates of angina in women remain an important finding. Further longitudinal population data are required to ascertain risk factors of angina in this population.

    Conclusions

    Angina is twice as common in women as men attending general practitioners in Goa and is especially higher in women aged 45–60 years. Moderate to high risk of depressive and anxiety symptoms was strongly associated with angina. General practitioner must be aware of the extent of angina and the higher prevalence in women among people attending general practices.

    Acknowledgments

    We would like to acknowledge the nine general practitioners doctors who took part in the study and the patients who undertook the research assessments. We would like to acknowledge the six researchers who conducted the research assessments and interviews.

    References

    1. ↵
      1. Gupta R,
      2. Misra A,
      3. Pais P,
      4. et al
      . Correlation of regional cardiovascular disease mortality in India with lifestyle and nutritional factors. Int J Cardiol 2005;108:291–300.
      OpenUrlPubMedWeb of Science
    2. ↵
      1. Ramachandran A,
      2. Snehalatha C,
      3. Latha E,
      4. et al
      . Clustering of cardiovascular risk factors in urban Asian Indians. Diabet Care 1998;21:967–71.
      OpenUrlAbstract/FREE Full Text
    3. ↵
      1. Mohan V,
      2. Deepa R,
      3. Rani SS,
      4. et al
      . The Chennai Urban Population Study. Prevalence of coronary artery disease and its relationship to lipids in a selected population in South India: The Chennai Urban Population Study (CUPS No. 5). J Am Coll Cardiol 2001;38:682–7.
      OpenUrlCrossRefPubMedWeb of Science
    4. ↵
      1. Ahmad N,
      2. Bhopal R
      . Is coronary heart disease rising in India? A systematic review based on ECG defined coronary heart disease. Heart 2005;91:719–25.
      OpenUrlAbstract/FREE Full Text
    5. ↵
      1. Bhopal R
      . What is the risk of coronary heart disease in South Asians? A review of UK research. J Public Health 2000;22:375–85.
      OpenUrlAbstract/FREE Full Text
    6. ↵
      1. Bhopal R,
      2. Unwin N,
      3. White H,
      4. et al
      . Heterogeneity of coronary heart disease risk factors in Indian, Pakistanis, Bangladeshi and European origin populations: cross sectional study. Br Med J 1999;319:215–20.
      OpenUrlAbstract/FREE Full Text
    7. ↵
      1. Williams R,
      2. Bhopal R,
      3. Hunt K
      . The health of a Punjabi ethnic minority in Glasgow: a comparison with the general population. J Epidemiol Community Health 1993;47:96–102.
      OpenUrlAbstract/FREE Full Text
    8. ↵
      1. Nazroo JY
      . The health of Britain's ethnic minorities. London: Policy Studies Institute, 1997.
    9. ↵
      1. Singh RB,
      2. Sharma JP,
      3. Rastogi V
      . Prevalence of coronary artery diseases and coronary risk factors in rural and urban populations of north India. Eur Heart J 1997;18:1728–35.
      OpenUrlAbstract/FREE Full Text
    10. ↵
      1. Gopinath N,
      2. Chadha SL,
      3. Jain P,
      4. et al
      . An epidemiological study of coronary heart diseases in different ethnic groups in Delhi urban population. J Assoc Phys India 1995;43:30–3.
      OpenUrl
    11. ↵
      1. Brugha R,
      2. Zwi A
      . Improving the quality of private sector delivery of public health services. Health Pol Plann 1998;13:107–20.
      OpenUrlAbstract/FREE Full Text
    12. ↵
      1. Zwi A,
      2. Brugha A,
      3. Smith E
      . Private health care in developing countries. BMJ 2001;323:463–4.
      OpenUrlFREE Full Text
    13. ↵
      1. Rose G
      . The diagnosis of ischaemic heart pain and intermittent claudication in field surveys. Bull World Health Organ 1962;27:645–58.
      OpenUrlPubMedWeb of Science
    14. ↵
      1. Sorlie PD,
      2. Cooper L,
      3. Schreiner PJ,
      4. et al
      . Repeatability and validity of the Rose questionnaire for angina pectoris in Artherosclerosis Risk in Communities Study. J Clin Epidemiol 1996;49:719–25.
      OpenUrlCrossRefPubMedWeb of Science
    15. ↵
      1. Oei HH,
      2. Vliegenthart R,
      3. Deckers JW,
      4. et al
      . The association of Rose Questionnaire angina pectoris and coronary clacification in a general population: the Rotterdam Coronary Calcification Study. Ann Epidemiol 2004;14:431–6.
      OpenUrlCrossRefPubMedWeb of Science
    16. ↵
      1. Fischbacher C,
      2. Bhopal R,
      3. Unwin N,
      4. et al
      . The performance of the Rose angina questionnaire in south Asians and European origin populations: a comparative study in Newcastle UK. Int J Epidemiol 2001;30:1009–16.
      OpenUrlAbstract/FREE Full Text
    17. ↵
    18. ↵
      1. Qureshi N,
      2. Bethea J,
      3. Modell B,
      4. et al
      . Collecting genetic information in primary care: evaluating a new family history tool. Fam Pract 2005;22:663–9.
      OpenUrlAbstract/FREE Full Text
    19. ↵
      WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implication for policy and intervention strategies. Lancet 2004;363:157–63.
      OpenUrlCrossRefPubMedWeb of Science
    20. ↵
      1. Kessler R,
      2. Andrews G,
      3. Hiripi E,
      4. et al
      . Short screening scales to monitor population prevalence and trends in non specific psychological distress. Psychol Med 2002;32:959–76.
      OpenUrlCrossRefPubMedWeb of Science
    21. ↵
      1. Patel V,
      2. Araya R,
      3. Chowdhury M,
      4. et al
      . Detecting common mental disorders in primary care in India: a comparison of five screening questionnaires. Psychol Med 2008;38:221–8.
      OpenUrlPubMedWeb of Science
    22. ↵
      StataCorp. Stata statistical software: release 9. College Station, TX: StataCorp LP, 2005.
    23. ↵
      1. Rao J,
      2. Scott A
      . The analysis of categorical data from complex sample surveys: chi-squared tests for goodness of fit and independence in two-way tables. J Am Stat Assoc 1981;76:221–230.
      OpenUrlCrossRefWeb of Science
    24. ↵
      1. Rao J,
      2. Scott A
      . On chi-squared tests for multiway contingency tables with cell proportions estimated from survey data. Ann Stat 1984;12:46–60.
      OpenUrlCrossRefWeb of Science
    25. ↵
      Census of India. Registrar general of births and deaths. ministry of home affairs. Government of India, 1991.
    26. ↵
      1. Reddy KS,
      2. Shah B,
      3. Varghese C,
      4. et al
      . Responding to the threat of chronic diseases in India. Lancet 2005;366:1744–9.
      OpenUrlCrossRefPubMedWeb of Science
    27. ↵
      1. Ramachandran A
      . Epidemiology of diabetes in India—three decades of research. J Assoc Phys India 2005;21:1414–31.
      OpenUrl
    28. ↵
      1. Mackay J,
      2. Mensah G
      . Atlas of heart diseases and stroke. 1st edn. World Health Organization, 2004.
    29. ↵
      1. Tunstall- Pedoe H,
      2. Kuulasmaa K,
      3. Mahonen M,
      4. et al
      . Contribution of trends in survival and coronary event rates to change coronary heart diasese mortality: 10 year results from 37 WHO MONICA project populations. Monitoring trends and determinants on cardiovascular disease. Lancet 1999;353:1547–57.
      OpenUrlCrossRefPubMedWeb of Science
    30. ↵
      1. Murabito JM,
      2. Evans JC,
      3. Larson MG,
      4. et al
      . Prognosis after the inset of cornonary heart diseases. An investigation of differences in outcome between the sexes according to initial coronary disease presentation. Circulation 1993;88:2548–55.
      OpenUrlAbstract/FREE Full Text
    31. ↵
      1. Hemingway H,
      2. McCallum A,
      3. Shipley M,
      4. et al
      . Incidence and prognostic implications of stable angina among women and men. JAMA 2006;295:1404–11.
      OpenUrlCrossRefPubMedWeb of Science
    32. ↵
      AIHW Australian GP Statistics and Classification centre. SAND abstract No 98 from the BEACH Program: management of hypertension and angina in general practice patients, 2007. Sydney: AGPSCC, University of Sydney. ISSN 1444-9072.
    33. ↵
      1. Saxena S,
      2. Car J,
      3. Eldred D,
      4. et al
      . Practice size, caseload, deprivation and quality of care of patients with coronary heart disease, hypertension and stroke in primary care: national cross-sectional study. BMC Health Serv Res 2007;7:96. doi:10.1186/1472-6963-7-96.
      OpenUrlCrossRefPubMed
    34. ↵
      1. Alexander P,
      2. Prabhu S,
      3. Krishnamoorthy E,
      4. et al
      . Mental disorders in patients with non cardiac chest pain. Acta Psychiatr Scand 1994;89:291–3.
      OpenUrlPubMedWeb of Science
    35. ↵
      1. Musselmann D,
      2. Tomer A,
      3. Manatunga A,
      4. et al
      . Exageerated platelet reactivity in major depression. Am J Psychiatry 1996;153:1313–17.
      OpenUrlPubMedWeb of Science
    36. ↵
      1. Cowen P
      . Cortisol, serotonin and depression: all stressed out? Br J Psychiatry 2002;180:99–100.
      OpenUrlFREE Full Text
    37. ↵
      1. O'Connor C,
      2. Gurbel P,
      3. Serebruany V
      . Depression and 18 months prognosis after myocardial infarction. Am Heart J 2000;140:S63–9.
      OpenUrlCrossRef
    38. ↵
      1. Kilkis B,
      2. Burgess M,
      3. Abidskov J
      . Influence of sympathetic tome on ventricular fibrillation threshols during experimental coronary occlusion. Am J Cardiol 1975;36:45–9.
      OpenUrlCrossRefPubMedWeb of Science
    39. ↵
      1. Jacka F,
      2. Pasco J,
      3. McConnell S,
      4. et al
      . Self-reported depression and cardiovascular risk factors in a community sample of women. Psychosomatics 2007;48:54–9.
      OpenUrlCrossRefPubMedWeb of Science
    40. ↵
      1. Jensen MSA,
      2. Thomsen JL,
      3. Jensen SE,
      4. et al
      . Prognosis of electrocardiographic abnormalities detected by screening. fremlagt ved PhD Day 2007. Århus.

    Footnotes

    • Funding The research was funded through a grant given by the University College London, UK. The funders had no direct role in the design or conduct of the study, interpretation of the data, or review of the manuscript.

    • Competing interests None.

    • Ethics approval Ethics approval was provided by the Independent Ethics Committee in Mumbai.

    • Provenance and peer review Not commissioned; not externally peer reviewed.