For the first time, researchers have shown that a bi-directional relationship exists between fatty liver disease and cardiovascular disease. Fatty liver disease can lead to increased cardiovascular disease risk and vice versa.
The findings are important in understanding the link between fatty liver disease and cardiovascular disease, which continues to be one of the major causes of morbidity and mortality worldwide.
Due to the increased prevalence of obesity, non-alcoholic fatty liver disease has become the most common liver disease in the US, affecting 20%-30% of the adult population. Obesity is also an independent risk factor for cardiovascular disease – so both diseases exist in many patients.
Previous studies have shown that there is a link between fatty liver and cardiovascular disease however it is not fully understood if fatty liver disease precedes or develops after cardiovascular disease.
Using data from participants in the Framingham Heart Study, researchers saw that individuals with fatty liver disease developed cardiovascular diseases such as high blood pressure and type 2 diabetes within six years. In a parallel analysis, individuals with high blood pressure, type 2 diabetes, or high triglycerides had a higher likelihood of developing fatty liver disease.
“In our study, we observed a bi-directional association between fatty liver and cardiovascular disease,” explained corresponding author Dr Michelle Long, assistant professor of medicine at Boston University School of Medicine (BUSM), who also is a gastroenterologist at Boston Medical Centre (BMC). “We observed that fatty liver was an important factor in the development of high blood pressure and diabetes and the opposite also stands true – various cardiovascular diseases were associated with the development of fatty liver disease over six years,” she added.
Long believes this study highlights the need to develop both preventative and treatment strategies for fatty liver disease in order to improve the cardiovascular health of all people.
Background & Aims: The relations of non-alcoholic fatty liver disease to cardiovascular disease (CVD) risk factors are not fully understood. The objective of our study is to explore the bi-directional relationships of fatty liver to CVD risk factors.
Methods: We prospectively evaluated whether liver fat predicted the development of CVD risk factors and whether CVD risk factors predicted new onset fatty liver during 6 years of follow-up in middle- to older-aged Framingham Heart Study participants. We estimated liver fat using multi-detector computed tomography.
Results: We included 1051 participants (mean age 45 ± 6 years, 46% women). The prevalence of fatty liver was 18% at baseline. In participants without fatty liver at baseline, 101 participants developed incident fatty liver over approximately 6 years. Baseline liver fat (per standard deviation increase) was associated with increased odds of incident hypertension (OR 1.42; 95% CI 1.15–1.76; p = 0.001) and incident type 2 diabetes (OR 1.43; 95% CI 1.09–1.88, p <0.001). In a parallel analysis, individuals with hypertension (OR 3.34; 95% CI 2.04–5.49), hypertriglyceridemia (OR 3.04; 95% CI: 1.84–5.02), impaired fasting glucose (OR 2.92; 95% CI 1.76–4.82), or type 2 diabetes (OR 4.15; 95% CI 1.19–14.46) at baseline had higher odds of incident fatty liver compared to individuals without those conditions (all p <0.03). In both analyses, the observed associations remained similar after additional adjustments for measures of adiposity.
Conclusions: The present study demonstrated bi-directional relationships between fatty liver and CVD risk factors among middle- to older-aged Framingham Heart Study participants.
Jiantao Ma, Shih-Jen Hwang, Alison Pedley, Joseph M Massaro, Udo Hoffmann, Raymond T Chung, Emelia J Benjamin, Daniel Levy, Caroline S Fox, Michelle T Long