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LONDON -- Non-alcoholic fatty liver disease (NAFLD) is an independent predictor of both type 2 diabetes and carotid atherosclerosis, according to two studies presented here at the annual meeting of the
A key implication of the findings is that people with NAFLD might be at risk for the other diseases, even if they don't have any of the traditional risk factors, according to , of Saarland University Hospital in Homburg, Germany, and a member of the association's governing board.
Action Points
- Note that these studies were published as abstracts and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
"You have to take the liver into account when you assess the risk for diabetes and cardiovascular risk," Lammert told reporters.
He said people being monitored for diabetes and heart disease should also be seen by liver specialists, and vice versa.
In a retrospective study conducted in Japan, people with NAFLD had nearly three times the risk of developing diabetes than people without the condition, according to Hajime Yamazaki, MD, of Teine Keijinkai Hospital in Sapporo, Japan, and colleagues.
Moreover, improvements in NAFLD reduced the risk of incident diabetes over about an 11-year follow-up, Yamazaki told an oral session.
Previous research on the issue has been inconclusive, Yamazaki said, with some short-term studies finding an increased risk, but a long cohort analysis finding nothing.
To help clear up the issue, he and colleagues looked at records for 8,070 patients who had voluntary checkups at least a decade apart and who had abdominal ultrasound at each visit.
Patients were excluded if they had hepatitis B or C, drank more than 20 g of alcohol a day, or had diabetes at the first visit, Yamazaki said. After the exclusions, the researchers were left with 3,074 participants, who were divided into 728 with NAFLD and 2,346 without NAFLD, based on their ultrasound results.
The group with NAFLD at baseline was then divided again -- into those who still had the condition at the second visit and those who no longer had it -- the "improved" subgroup.
Overall, incidence of type 2 diabetes was 6.1% over the follow-up, Yamazaki said, but was much higher among those with NAFLD at baseline -- 16.1% versus 3.1% among those without fatty liver.
After adjustment for age, sex, body mass index, family history, dyslipidemia, and hypertension, Yamazaki reported, those figures yielded an odds ratio for diabetes of 2.82 (95% CI 1.91-4.15, P<0.001).
Moreover, he reported, the 100 patients whose NAFLD improved over the 10 years had a much lower incidence of diabetes than the 618 who continued to have the condition -- 6.4% versus 17.8%.
The figures yielded an adjusted odds ratio for diabetes of 0.30 in favor of the improved group (95% CI 0.13-0.66, P=0.003).
In a later presentation in the same session, Raluca Pais, MD, of in Paris, and colleagues reported that NAFLD is an independent predictor of carotid atherosclerosis.
Pais noted that previous research has shown that patients with NAFLD have an increased prevalence of cardiovascular disease and that they tend to develop carotid atherosclerosis earlier that their healthy counterparts.
But it's not clear whether the fatty liver is an independent risk factor or has its effects through the underlying metabolic disorder.
To add to the information, she and colleagues studied the records of patients at high risk for cardiovascular events, who were being seen in a primary prevention program, with a view at assessing the impact of NAFLD on carotid atherosclerosis and .
They began with a cross-sectional snapshot of 5,671 patients with at least two cardiovascular risk factors and ultrasound measurements of carotid intima media thickness (C-IMT) carotid plaques. NAFLD was defined as a fatty liver index of 60 or greater, and the researchers used the gender-specific Framingham score sheet.
A subset of the participants was then followed for an average of 8 years, she reported.
The snapshot analysis showed that 33% of the patients had NAFLD, the average C-IMT was 0.63 millimeters, 39% had carotid plaques, and the average Framingham score was 10, Pais reported.
But all of the risk factors for cardiovascular disease were significantly more prominent among the 1,871 patients with NAFLD, including body mass index, waist circumference, diabetes, hypertension, smoking, and alcohol consumption.
In particular, the NAFLD participants had a greater C-IMT (0.64 millimeters versus 0.61), more plaque (44% versus 37%), and a higher Framingham score (15 versus eight).
Over the follow-up period, C-IMT, carotid plaque percentage, and the proportion of patients with NAFLD all rose, she noted, as did such things as average body mass index, waist circumference, and use of lipid-lowering drugs.
But only three baseline factors predicted carotid atherosclerosis -- age, tobacco use, and NAFLD, she said.