Doctoral dissertation

Ulla Nivukoski: Separate and Combined Effects of Lifestyle Risk Factors on Biomarkers of Liver Function, Inflammation and Lipid Status

Ulla Nivukoski
Health problems associated with lifestyle are becoming increasingly common in modern societies. The main lifestyle risk factors which contribute to the incidence of chronic diseases and premature death include alcohol drinking, cigarette smoking, excess body weight, physical inactivity and poor diet. On the other hand, a lack of lifestyle-related risk factors has been shown to be associated with prolonged life expectancy.

M.S. Ulla Nivukoski studied in her doctoral dissertation the associations between lifestyle risk factors and biomarkers of liver function, inflammation and lipid status in a large population- based sample (the National FINRISK Study). The material had been collected from six geographical areas in Finland during the years 1997, 2002 and 2007 and provided an age and gender-stratified random sample which included 22,327 apparently healthy individuals aged 25–74 years. Data on health status, alcohol consumption, smoking, physical activity and coffee drinking were collected from structured interviews and questionnaires, and, weight, height and waist circumference were ascertained by means of physical measurements. Self-reported alcohol consumption data for the past 12 months were used to classify the participants into subgroups of abstainers and World Health Organization (WHO) risk drinking categories representing low, moderate, high and very high risk drinkers. The participants were also classified into subgroups according to their frequencies of binge drinking. Serum liver enzymes (gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT), C-reactive protein (CRP) and lipid profiles were measured using standard laboratory procedures. Risk scores for the lifestyle factors (alcohol consumption, cigarette smoking, physical inactivity and excess body weight) were established on a 0–8 scale and used to classify the population into lifestyle-related risk categories, which also allowed estimation of the joint effects of the various lifestyle factors.

The WHO risk drinking category was fairly well linearly related to the occurrence of elevated GGT, ALT and CRP values, and alcohol drinking was also a significant determinant of serum lipid abnormalities. Significantly higher odds for abnormal GGT, ALT and lipid profiles were found in the alcohol drinkers after adjustment for age, waist circumference, physical activity, smoking and coffee intake, while the frequency of binge-type drinking showed a significant association with GGT levels in both men (p < 0.0005) and women (p < 0.0005) and with ALT in men (p < 0.0005). Even among the individuals with low risk total alcohol consumption, higher GGT (p < 0.0005) and ALT (p < 0.0005) activities were observed in those with binge drinking episodes more than once a month than in those with no such episodes.

Distinct dose-response associations were found between the total number of lifestyle-related risk factors and serum ALT, GGT, CRP, cholesterol, high-density lipoprotein, low-density lipoprotein and triglycerides (p < 0.0005 for a linear trend in all comparisons). When compared with the subjects without any risk factors, the multivariable-adjusted odds ratios for abnormalities in all biomarkers were significantly higher in those with a risk score of two or more. The most notable increases in ORs in the subjects with high numbers of risk factors were observed among men with respect to serum GGT: 26.6 (12.4–57.0), ALT: 40.3 (5.3–307.8), CRP: 16.2 (7.8–33.7) and serum triglycerides: 14.4 (8.6–24.0). The occurrence of a fatty liver index (FLI) ≥ 60 indicating the presence of fatty liver, increased from 2.4% in men with zero risk factors to 81.9% in those with a risk score of 7–8 (p < 0.0005 for a linear trend) and from 0% to 73.5% in women (p < 0.0005). The most striking impacts on the likelihood of FLI ≥ 60 were observed for physical inactivity (p < 0.0005 for both genders) and alcohol consumption (p < 0.0005 for men).

The data indicate that systematic use of laboratory tests may improve the assessment of health risks related to lifestyle and behaviour. These results also emphasize the adverse effects of binge-type alcohol drinking on hepatic function even in individuals with low-risk overall alcohol consumption. Combinations of several unfavourable lifestyle factors are associated with distinct abnormalities in laboratory tests for liver function, inflammation and lipid status and a high likelihood of hepatic steatosis. The use of biomarkers could also benefit the assessment of interventions aimed at maintaining a healthy lifestyle.

The doctoral dissertation of M.S. Ulla Nivukoski in the field of laboratory medicine titled Separate and combined effects of lifestyle risk factors on biomarkers of liver function, inflammation and lipid status will be publicly examined at the Faculty of Medicine and Health Technology of Tampere University at 12 o'clock on Friday 23 April, 2021. Professor Esa Hämäläinen from University of Eastern Finland will be the opponent while Professor Onni Niemelä will act as the custos.

The event can be followed via remote connection

The dissertation is available online at
http://urn.fi/URN:ISBN:978-952-03-1905-2

Photo: Juha-Matti Nivukoski

 

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