This study accumulated 153 750 person-years of follow-up. Irrespective of the type of chest pain, South Asian participants tended to be older, less likely to have smoked, more likely to be hypertensive and diabetic, more likely to live with a partner, have a higher prevalence of metabolic syndrome and be in lower employment grades of work than White participants (Table ). Among both ethnic groups, there was an increasing prevalence of hypertension and higher cholesterol levels and trends towards more metabolic syndrome and higher body mass index with more typical chest pain, but no other similar trends were observed. In particular, neither glucose intolerance nor diabetes mellitus had a significant relationship with the presence/absence of chest pain or chest pain types, in both populations studied.
Baseline characteristics in each chest pain type comparing South Asian and White participants
Incidence of different forms of chest pain by ethnic group
At Phase 1, South Asian participants had a higher prevalence of typical angina compared with White participants (4.8 versus 2.8%, P = 0.019) and exertional chest pain (7.8 versus 4.1%, P < 0.001) but not non-exertional chest pain (22.2 versus 25.2%, P = 0.085), as depicted in Fig. . By Phase 7, South Asian participants had higher cumulative frequencies of typical angina (17.0 versus 11.3%, P < 0.001) and exertional chest pain (15.4 versus 8.5%, P < 0.001) compared with White participants. For non-exertional chest pain, South Asian participants had a lower cumulative frequency (24.6 versus 31.3%, P = 0.001) compared with White participants.
Cumulative incidence of different types of chest pain by ethnic group over seven study phases.
Prognosis within ethnic groups of those with pain compared with those with no chest pain
In both South Asian and White participants, those with baseline typical angina and exertional chest pain had a worse prognosis for the long-term coronary outcome compared with those with no baseline chest pain. HR were similar in magnitude (in South Asian participants with typical angina adjusted: HR, 4.67 and 95% CI, 2.12–10.30; in White participants with typical angina adjusted: HR, 3.56 and 95% CI, 2.59–4.88, Table ). Baseline non-exertional chest pain was not associated with a worse prognosis in either ethnic group.
Risk for coronary death and non-fatal myocardial infarction, comparing types of chest pain with those with no chest pain, and comparing South Asian with White participants by type of chest pain
Prognosis within types of pain for South Asian compared with White participants
Among those with typical angina at baseline, South Asian participants had a worse long-term prognosis than White participants: HR, 2.56 and 95% CI, 1.36–4.84, Table ). The South Asian population also had a worse long-term prognosis than the White population in those with non-exertional chest pain, and there was a similar trend in those with exertional chest pain and no chest pain. Across all types of chest pain, the rates of CHD events were higher in South Asian participants. A likelihood ratio test revealed no interaction between ethnicity and chest pain (P = 0.720).