Published online Feb 7, 2019. doi: 10.3748/wjg.v25.i5.600
Peer-review started: December 6, 2018
First decision: December 28, 2018
Revised: January 10, 2019
Accepted: January 14, 2019
Article in press: January 14, 2019
Published online: February 7, 2019
Processing time: 55 Days and 20.1 Hours
Malnutrition with deficiencies of fat-soluble vitamins, minerals and trace elements are well-known consequences of maldigestion and poor absorption of nutrients. Malnutrition has been frequently identified in patients with chronic pancreatitis (CP) and pancreatic exocrine insufficiency (PEI). Zinc is important for normal functioning of immune system and its deficiency was recognized more than 50 years ago. Studies analyzing zinc levels in patients with CP are sparse and lead to conflicting results. However, studies analyzing zinc levels in patients with CP are sparse and most of them included only patients with alcoholic etiology. In this study, prevalence and risk factors of zinc deficiency in a large number of patients with different etiologies of CP were determined.
The main topic was zinc insufficiency and its relation to patients’ demographic and clinical parameters: Gender, age, smoking, alcohol intake, body mass index (BMI), diabetes mellitus (DM), bone mineral density, PEI and etiology of CP.
In this large study of 150 patients with CP, one in four patients was shown to have a zinc deficiency, which was the main objective. Zinc deficiency was not related to gender, BMI, etiology of CP, presence of DM, bone mineral density and alcohol intake. It is of significance that zinc deficiency was present in patients with and without PEI, suggesting that impaired secretion of pancreatic enzymes is not the main factor resulting in a reduced absorption or increased excretion of zinc. These objectives should be better analyzed in future research in this field.
We performed retrospective analysis of demographic, clinical and laboratory data, with detailed information on alcohol intake and smoking status. For former or current smokers, the number of cigarettes per day over a given number of years was recorded, and pack-years were calculated accordingly. Results showed that smoking status was very important in this study: Number of pack-years was correlated with low zinc levels and the risk of zinc deficiency in current smokers and smokers with ≥ 20 pack-years was approximately three times higher compared to those who had never smoked.
We showed that zinc deficiency is significantly associated with higher age, smoking and the number of pack-years. On the other hand, zinc deficiency was not related to gender, BMI, etiology of CP, presence of DM, bone mineral density, alcohol intake and presence of PEI. The fact that zinc deficiency was present in patients with and without PEI is very important. Future studies on this topic are necessary for better understanding of mechanisms included in zinc insufficiency.
This is the first study to analyze the prevalence and risk factors of zinc deficiency in a large number of patients with different etiologies of CP. One in four patients was shown to have a zinc deficiency. There is significant association of zinc deficiency with higher age, smoking and the number of pack-years. We showed no correlation of zinc deficiency with gender, BMI, etiology of CP, presence of DM, bone mineral density, alcohol intake and presence of PEI. Due to the lower sensitivity of the fecal elastase-1 test for diagnosing mild and moderate forms of CP, the true prevalence of PEI may be underestimated. Future studies with 13C-mixed triglyceride breath test, which has a higher sensitivity for detecting PEI compared to a standard fecal elastase-1 test, can help us to solve this problem.
Assessing zinc levels in the plasma represents a limitation of the present study. Future studies with measuring of zinc in erythrocytes can be of interest due to the advantage of reflecting the zinc status over a longer period compared to the rapid turnover of the plasma pool of zinc. Impaired secretion of pancreatic enzymes is probably not the main factor resulting in a reduced absorption or increased excretion of zinc. Future studies on this topic are necessary. The results from the present study suggest that zinc deficiency is relatively common in patients with CP. Clinicians dealing with CP, regardless of etiology, should be aware of the clinical importance of zinc malnutrition, especially in older patients and smokers.