Excellent agreement between genetic and hydrogen breath tests for lactase deficiency and the role of extended symptom assessment.

Clinical manifestations of lactase (LCT) deficiency include intestinal and extra-intestinal symptoms. Lactose hydrogen breath test (H2-BT) is considered the gold standard to evaluate LCT deficiency (LD). Recently, the single-nucleotide polymorphism C/T(-13910) has been associated with LD. The objectives of the present study were to evaluate the agreement between genetic testing of LCT C/T(-13910) and lactose H2-BT, and the diagnostic value of extended symptom assessment. Of the 201 patients included in the study, 194 (139 females; mean age 38, range 17-79 years, and 55 males, mean age 38, range 18-68 years) patients with clinical suspicion of LD underwent a 3-4 h H2-BT and genetic testing for LCT C/T(-13910). Patients rated five intestinal and four extra-intestinal symptoms during the H2-BT and then at home for the following 48 h. Declaring H2-BT as the gold standard, the CC(-13910) genotype had a sensitivity of 97% and a specificity of 95% with a κ of 0.9 in diagnosing LCT deficiency. Patients with LD had more intense intestinal symptoms 4 h following the lactose challenge included in the H2-BT. We found no difference in the intensity of extra-intestinal symptoms between patients with and without LD. Symptom assessment yielded differences for intestinal symptoms abdominal pain, bloating, borborygmi and diarrhoea between 120 min and 4 h after oral lactose challenge. Extra-intestinal symptoms (dizziness, headache and myalgia) and extension of symptom assessment up to 48 h did not consistently show different results. In conclusion, genetic testing has an excellent agreement with the standard lactose H2-BT, and it may replace breath testing for the diagnosis of LD. Extended symptom scores and assessment of extra-intestinal symptoms have limited diagnostic value in the evaluation of LD.

Lack of association between iron metabolism and depressive mood in an elderly general population.

BACKGROUND: Alterations in iron metabolism have been suggested as potential pathological markers in patients with manifest depression. No data on the association between iron and depression exist from population-based studies, in which milder forms of depressive symptoms are much more common. The aim of this study was to analyze the relationship between six parameters of iron metabolism and depressive mood in a population-based cross-sectional study in Germany. METHODS: A total of 374 participants, aged 65-83 years, of the Memory and Morbidity in Augsburg Elderly (MEMO) Study were assessed using the Center for Epidemiologic Studies - Depression Scale (CES-D) for depression. Iron, ferritin, transferrin, soluble transferrin receptor, iron binding capacity, transferrin saturation and C-reactive protein were analyzed with standard laboratory methods. Linear and logistic regression analyses were applied to evaluate the relationship between iron parameters and depressive mood. RESULTS: The 7-day prevalence of depressive mood was 10.2%, with a higher risk in women compared to men [odds ratio (OR) = 2.04; 95% confidence interval (95% CI) = 1.04-4.0]. Correlation and linear regression analyses adjusted for age, gender, hypertension and smoking yielded no significant relationship between any of the iron parameters and the CES-D scores. In gender-stratified analyses a statistically significant association between serum iron and depressive mood was observed in men only. This finding disappeared after applying a Bonferroni correction for multiple testing. CONCLUSIONS: The lack of association of iron metabolism and depressive mood reported in this population-based study does not support previous findings in patients with major depression. This negative finding in milder forms of depression in elderly people indicates either the absence or a more complex nature of the interactions between iron metabolism, low-grade inflammation and depression.