Nonalcoholic fatty liver disease associated with obstructive sleep apnea: just a coincidence?
BACKGROUND
Obesity is associated with obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD). It has been shown that OSA could be an independent risk factor for NAFLD. OSA could cause not only insulin resistance but worse NAFLD through nocturnal hypoxemia. This study aimed to evaluate the frequency of OSA and NAFLD in obese patients and the relationship between OSA, insulin resistance, and severity of steatohepatitis (nonalcoholic steatohepatitis (NASH)).


METHODS
Forty obese patients submitted to bariatric surgery were evaluated. Sleep studies, fasting blood glucose, serum insulin, homeostasis model assessment (HOMA-IR), and liver enzymes were measured. Liver biopsies were evaluated for features of NAFLD including degrees of steatosis, inflammation, cellular ballooning, and fibrosis. NASH was diagnosed in those with steatosis + ballooning or steatosis + fibrosis. The diagnosis of OSA was based on an apnea/hypopnea index (AHI) ≥ 5 events/hours.


RESULTS
OSA was present in 32 (80.0%), NAFLD in 33 (82.5%), and NASH in 32 (80.0%) patients. Patients with AHI ≥ 15 ev/h had higher serum insulin levels (30.0 ± 12.8 vs. 22.6 ± 17.3 μU/ml; p = 0.015) and HOMA-IR (7.5 ± 4.0 vs. 5.4 ± 4.1; p = 0.016) when compared with those with AHI < 15 ev/h, but no association was found between AHI and NASH (81.0% vs. 78.9%; p = 1.000) or oxihemoglobin desaturation <84% and NASH (81.2% vs. 70.8%; p = 0.709) when these groups were compared.


CONCLUSIONS
Obese patients had elevated OSA and NAFLD frequencies. OSA was associated with insulin resistance but not with the severity of NASH.
Daltro
Carla
C
Department of Internal Medicine, Bahiana School of Medicine and Public Health, Rua Clarival do Prado Valladares, 264/803, Salvador, Bahia, 41.820-700, Brazil. carlahcd@terra.com.br
Cotrim
Helma P
HP
Alves
Erivaldo
E
de Freitas
Luiz Antônio
LA
Araújo
Leila
L
Boente
Leonardo
L
Leal
Rafael
R
Portugal
Thaís
T
D000328:Adult; D050110:Bariatric Surgery; D005234:Fatty Liver / Q000150:complications; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D009765:Obesity / Q000150:complications* / Q000601:surgery; D020181:Sleep Apnea, Obstructive / Q000150:complications*