Risk of cardiovascular diseases and predictors of cardiometabolic disease in Hong Kong Chinese : a clinical study

Abstract

Cardiovascular diseases are the number one cause of death worldwide and have remained a major cause of premature deaths and chronic disabilities across all regions. In 2017, it was estimated that there were 17.8 million deaths from CVDs, which accounted for 31% of all global deaths. The World Health Organization (WHO) has estimated that over 75% of CVDs are preventable and that risk factor amelioration can help to reduce the morbidity and mortality burden. The 10-year risk of CVDs can be estimated using prediction models, which can be applied at both the individual and population level. On an individual level, CVD risk prediction allows primary healthcare professionals to identify high-risk patients. The risk factors of CVDs, such as hypertension, can then be treated accordingly to reduce the patient's future risk of developing CVDs. On a population level, the use of risk prediction models allows health policy planners to make evidence-based decisions and to review current public health strategies used in CVD prevention. In the first part of the thesis, we illustrated the change in sex-age specific Framingham CVD risk in a general population by using the Hong Kong Population Health Survey (PHS) 2014-2015 with the previous survey conducted in 2003-05 (Population Health Survey (PHS)2003/2004 & Heart Health Survey (HHS) 2004/2005). By adjustment to the US census standard population, the age-standardized CVD risk was lower in 2014-2015 compared to that of 2003-05 (10.0% vs. 10.7%, p<0.001). Largest decrease in predicted CVD risk was observed among subjects aged 65-74 (26.4% in 2003-2005 vs. 24.0% in 2014-15). In addition, significantly more participants aged 65-74 were classified as high risk during 2003/04 (PHS2003/2004 & HHS2004/2005: 66.8% vs. PHS2014/15: 53.1%, p=0.028). This coincided with a decrease in the proportion of male smokers (30.0% in 2003-2005 vs 23.5% in 2014-15, p<0.001). Apart from clinical risk factors, serum levels of cardiometabolic biomarkers were also found to correlate with cardiovascular risk factors. In the latter part of the thesis, the potential role of Growth differentiation Factor 15 (GDF15) as a cardiometabolic biomarker in healthy subjects was elucidated. The relationship between serum levels of GDF15, other cardiometabolic biomarkers (Adiponectin, Galectin 3, Beta 2 microglobulin, C- reactive protein) and anthropometric measurements in healthy participants were explored. In chapter 5, a positive correlation between serum GDF15 levels and waist circumference was shown. However, no relationship was found between the serum level of GDF15 and other cardiometabolic biomarkers in healthy subject.