Physical activity, sedentary time, and liver enzymes in adolescents: the HELENA study

Abstract

Background:To examine the association between physical activity (PA) and liver enzyme levels in adolescents from nine European countries. Methods: The study comprised 718 adolescents (397 girls). PA was measured by accelerometry and expressed as total PA (counts/min), and time (min/d) engaged in moderate to vigorous intensity PA (MVPA). Time spent sedentary was also objectively measured. We measured serum levels of alanine aspartate aminostrasferase (AST), alanine aminostransferase (ALT), and γ-glutamyltrasnferase (GGT), and the AST/ALT ratio was computed. results: There was an association between MVPA and AST and AST/ALT (age, sex, and center-adjusted β = 0.096, 95% confidence interval (CI): 0.016 to 0.118; and β = 0.090, 95% CI: 0.006 to 0.112, respectively). Meeting the PA recommendations (60 min/d of MVPA) was significantly associated with higher AST and AST/ALT, which persisted after further adjusting for sedentary time and waist circumference. Sedentary time was not associated with any of the studied liver enzyme levels. conclusion: Meeting the current PA recommendations of 60 min/d of MVPA is associated with higher levels of AST and AST/ALT regardless of time spent sedentary as well as total and central body fat in European adolescents. n onalcoholic fatty liver disease (NAFLD) is the most common cause of abnormal liver function in young people (1), and is reaching epidemic proportions (2). Increased serum liver enzyme levels such as alanine aminostransferase (ALT), γ-glutamyltrasnferase (GGT), and even aspartate aminostrasferase (AST) are considered surrogate markers of NAFLD (2). These enzymes are associated with total and central body fat, insulin resistance, and blood lipids in children and adolescents (3-6), and are known to track from childhood to adulthood (7).Several studies in middle-and older-aged populations showed an association of liver enzyme levels with metabolic syndrome and type 2 diabetes (8)(9)(10)(11)(12). Hanley et al. (13) showed that adults with higher levels of AST-to-ALT ratio (AST/ALT) had lower risk of metabolic syndrome. Of note is that whereas an AST/ALT level <1 is indicative of nonalcoholic steatohepatitis, a ratio of ≥2 is associated with alcoholic liver disease (14). Lu et al. (15) showed that Han young adults with AST/ALT <1 had a higher frequency of abdominal obesity, high triglycerides, elevated blood pressure, and metabolic syndrome. More recently, a longitudinal study in young adults showed that both ALT and GGT levels predicted 16-y incidence of type 2 diabetes (16). Therefore, a greater indepth knowledge of the factors affecting liver enzymes and NAFLD in youth will contribute to the development of effective prevention programs, counseling, and public health policy.It is known that moderate to vigorous physical activity (MVPA) is associated with a healthier body composition (17)(18)(19)(20), metabolic profile (21,22), and insulin sensitivity (23) in youth. Moreover, there is no doubt regarding the detrimental consequences for health of a prolonged sedentary lifest...

Physical Activity Is Prospectively Associated With Adolescent Nonalcoholic Fatty Liver Disease

“…AST is abundant in muscle cells, and studies have reported greater physical activity, particularly vigorous activity, to be associated with higher circulating levels possibly because of muscle cell breakdown (39)(40)(41). Consistent with this and our findings, a recent cross-sectional study found that adolescents achieving daily recommended time spent in objectively measured MVPA (compared with those not achieving this recommendation) had lower GGT and ALT but higher AST (42).…”

Objectively measured sedentary behaviour and health and development in children and adolescents: systematic review and meta‐analysis

“…Two studies investigated associations between the total volume of sedentary behaviour and liver enzymes (Table S16). The study of Ruiz et al was classified as low ROB and found no significant associations between overall sedentary behaviour and liver enzymes among 12‐ to 18‐year‐old adolescents ( n = 718). In contrast, another study that was not classified as low ROB and that did not adjust for MVPA found that total sedentary time was detrimentally associated with liver enzymes in 7‐ to 15‐year‐olds .…”

Exercising the hepatobiliary‐gut axis. The impact of physical activity performance

“…1 Sedentary behaviour, in contrast, affects negatively cardiovascular risk factors 2 and represents 23% of the deaths related to chronic diseases. 1 Sedentary behaviour, in contrast, affects negatively cardiovascular risk factors 2 and represents 23% of the deaths related to chronic diseases.…”

“…The beneficial effects of physical activity are shown on several health outcomes, such as cardiovascular disease (CVD) and mortality for all causes. 1 Sedentary behaviour, in contrast, affects negatively cardiovascular risk factors 2 and represents 23% of the deaths related to chronic diseases. 3 Being inactive for several years may lead to increased risks for type 2 diabetes (T2D), CVD and premature mortality.…”