Stroke risk varies by ethnicity in Singapore

Ethnic differences emerge in stroke patterns within Singapore, with a study finding showing that Indians have lower rates of haemorrhagic stroke and a lower proportion of female patients compared with the Chinese and Malay populations.

For the study, researchers collected data on 1,165 stroke patients admitted to Raffles Hospital (2015–2023) to explore the profile for stroke risk among the Chinese, Malays, and Indians in Singapore. Of note, the patients had a mean age of 65.6 years, and most were male (52.6 percent) and of Chinese ethnicity (83 percent). [J Cardiovasc Dev Dis 2024;11:180]

The most common risk factors were hypertension (63.5 percent) and hyperlipidemia (60.3 percent), followed by smoking (35.6 percent) and diabetes mellitus (31.8 percent). There were 24.2 percent of patients with previous cerebrovascular events.

Stroke was mostly due to infarction (76.5 percent vs 23.5 percent for haemorrhage), and many ischaemic strokes were due to small artery occlusion (38.8 percent) and lacunar syndrome (56.6 percent), according to the TOAST* and OCSP** criteria, respectively.

Compared with ischaemic stroke, haemorrhagic stroke was positively associated with hypertension (adjusted odds ratio [aOR], 1.70, 95 percent confidence interval [CI], 1.13–2.56; p=0.011) and negatively associated with diabetes mellitus (aOR, 0.31, 95 percent CI, 0.20–0.48; p<0.001) and smoking (aOR, 0.40, 95 percent CI, 0.28–0.56; p<0.001).

“When the ethnicities were compared, there were notable differences in sex and stroke mechanism,” according to the researchers.

Specifically, female stroke patients were fewer among Indians and other ethnicities than among the Chinese people and Malays (31.4 percent and 22.2 percent vs 49.3 percent and 44.7 percent, respectively; p=0.005), as were haemorrhagic stroke events (9.3 percent and 0.7 percent vs 24.5 percent and 26.2 percent, respectively; p=0.014).

The demographics and risk factor profile observed in the current study were in line with the factors considered by stroke risk factor calculators such as the Framingham Stroke Profile, as the researchers pointed out. Furthermore, the data shows consistency with established stroke risk factors in Asian populations. [Stroke 1991;22:312–318; J Stroke 2017;19:286-294]

Meanwhile, “the significant association of stroke subtype with ethnicity is the novel finding of this study. [This] provides novel data that allow direct and detailed inter-ethnic comparison of hospitalized stroke patients, which may impact on stroke prevention and management in specific ethnicities,” they said.

However, the researchers acknowledged that the role of several other factors—which include obesity, exercise, diet, obstructive sleep apnoea, genetics, socioeconomic status, chronic infections, and inflammation markers—were not evaluated in the study.

As such, additional “multicentre, multi-ethnic studies with large sample sizes would be needed to corroborate the findings of this study and to uncover additional reasons for the [ethnicity-specific] differences [in the profile for stroke risk],” they added.

*Trial of Org10172 in Acute Stroke Treatment

**Oxfordshire Community Stroke Project