Athanassios Petralias

Oral ingestion of hexavalent chromium through drinking water and cancer mortality in an industrial area of Greece - An ecological study

BackgroundHexavalent chromium is a known carcinogen when inhaled, but its carcinogenic potential when orally ingested remains controversial. Water contaminated with hexavalent chromium is a worldwide problem, making this a question of significant public health importance.MethodsWe conducted an ecological mortality study within the Oinofita region of Greece, where water has been contaminated with hexavalent chromium. We calculated gender, age, and period standardized mortality ratios (SMRs) for all deaths, cancer deaths, and specific cancer types of Oinofita residents over an 11-year period (1999 - 2009), using the greater prefecture of Voiotia as the standard population.ResultsA total of 474 deaths were observed. The SMR for all cause mortality was 98 (95% CI 89-107) and for all cancer mortality 114 (95% CI 94-136). The SMR for primary liver cancer was 1104 (95% CI 405-2403, p-value < 0.001). Furthermore, statistically significantly higher SMRs were identified for lung cancer (SMR = 145, 95% CI 100-203, p-value = 0.047) and cancer of the kidney and other genitourinary organs among women (SMR = 368, 95% CI 119-858, p-value = 0.025). Elevated SMRs for several other cancers were also noted (lip, oral cavity and pharynx 344, stomach 121, female breast 134, prostate 128, and leukaemias 168), but these did not reach statistical significance.ConclusionsElevated cancer mortality in the Oinofita area of Greece supports the hypothesis of hexavalent chromium carcinogenicity via the oral ingestion pathway of exposure. Further studies are needed to determine whether this association is causal, and to establish preventive guidelines and public health recommendations.

An improved method for the computation of the Moore―Penrose inverse matrix

Abstract In this article we provide a fast computational method in order to calculate the Moore–Penrose inverse of singular square matrices and of rectangular matrices. The proposed method proves to be much faster and has significantly better accuracy than the already proposed methods, while works for full and sparse matrices.

An MCMC model search algorithm for regression problems

In this paper, we improve upon the Carlin and Chib Markov chain Monte Carlo algorithm that searches in model and parameter spaces. Our proposed algorithm attempts non-uniformly chosen ‘local’ moves in the model space and avoids some pitfalls of other existing algorithms. In a series of examples with linear and logistic regression, we report evidence that our proposed algorithm performs better than the existing algorithms.

The impact of a school food aid program on household food insecurity.

Background: We had a unique opportunity to establish the extent of food insecurity and the potential impact of a large-scale school-based nutritional program, in low-socioeconomic status districts of Greece, during the current economic crisis. Methods: Around 162 schools with 25 349 students participated during the 2012–2013 school year. Each student received a daily healthy meal designed by nutrition specialists. Food insecurity levels, measured using the Food Security Survey Module were assessed at baseline and after a 1–8-month intervention period. Pre–post intervention responses were matched at an individual level. Results: Around 64.2% of children’s households experienced food insecurity at baseline. This percentage decreased to 59.1% post-intervention, P < 0.001. On an individual level, food insecurity score diminished by 6.5%, P < 0.001. After adjustment for various socioeconomic factors, for each additional month of participation, the odds of reducing the food insecurity score increased by 6.3% (OR = 1.06, 95% CI: 1.02–1.11). Those experiencing food insecurity with hunger at baseline were more likely to improve food insecurity score than those who did not (OR = 3.51, 95%CI: 2.92–4.21). Conclusion: Children and families residing in low socioeconomic areas of Greece, experience high levels of food insecurity. Our findings suggest that participation in a school-based food aid program may reduce food insecurity for children and their families in a developed country in times of economic hardship.

The influence of a school-based intervention programme regarding adherence to a healthy diet in children and adolescents from disadvantaged areas in Greece: the DIATROFI study

Background To evaluate the effects, via a cohort study, of a food aid and promotion of healthy nutrition programme, implemented in areas of low socioeconomic status (SES) in Greece, on students’ diet quality. Methods From a total of 162 schools participating in the programme during the 2012–2013 school year, we collected 3941 individually linked questionnaires at baseline and at the end of the intervention, recording sociodemographic characteristics, lifestyle parameters and dietary habits of the students. For the assessment of diet quality, the KIDMED score was computed, along with food frequency consumption data regarding milk, fruits, vegetables and whole grain products. Pre–post intervention values were compared using non-parametric tests. Generalised estimating equations were used to explore the factors that influence changes in dietary habits. Results By the end of the intervention, favourable changes were observed regarding healthy eating; KIDMED increased statistically significantly in adolescent girls (p=0.042), while the consumption frequency of all foods promoted by the intervention, namely, milk, fruits, vegetables and whole grain products, increased for children and adolescents, boys and girls (p≤0.002). Factors indicating lower SES, such as foreign country of birth, lower education level, no income source and high levels of food insecurity, were associated with lower diet quality. Conclusions As low SES groups tend to adopt unhealthier dietary choices, it is of the outmost importance to take action for the promotion of healthy eating, directed especially to these at risk populations. School-based nutritional programmes can be considered as an effective policy measure towards this direction.

The effect of Greek herbal tea consumption on thyroid cancer: a case-control study

BACKGROUND Although in the last decade several studies have addressed the protective role of black and green tea on several diseases, including cancer, there are only few and controversial studies on the effect of tea on benign and malignant thyroid diseases. METHODS An age and gender group matched case-control study conducted in Athens, Greece, was designed. 113 Greek patients with histologically confirmed thyroid cancer and 286 patients with benign thyroid diseases along with 138 healthy controls were interviewed with a pre-structured questionnaire in person by trained interviewers. RESULTS An inverse association between chamomile tea consumption and benign/malignant thyroid diseases was found (P < 0.001). The odds of chamomile tea consumption, two to six times a week, after controlling for age, gender and BMI, were 0.30 (95% CI: 0.10-0.89) and 0.26 (95% CI: 0.12-0.5) for developing thyroid cancer and benign thyroid diseases, respectively when compared with not consumption. The duration of consumption was also inversely associated with the diseases. Thirty years of consumption significantly reduced the risk of thyroid cancer and benign thyroid diseases development by almost 80%. Similar, although weaker protective association, was found for sage and mountain tea. Adjustment for smoking, alcohol and coffee consumption did not alter the results. CONCLUSIONS Our findings suggest for the first time that drinking herbal teas, especially chamomile, protects from thyroid cancer as well as other benign thyroid diseases.

Commentary on: A prospective comparison of patient body image after robotic thyroidectomy and conventional open thyroidectomy in patients with papillary thyroid carcinoma

ROBOTIC THYROIDECTOMY (RT), as described and applied in large numbers of patients in Korea, has been to many a revolution in modern thyroid surgery. A thyroidectomy without an incision in the neck is appealing to many patients and some surgeons. In this report, the leaders of the transaxillary robot-assisted thyroidectomy approach are comparing their novel technique with conventional open thyroidectomy (OT) and asking the question whether RT provides a better self-body image and improved quality of life (QoL) than the conventional approach. Their answer favors RT, but we are not convinced with the data presented in this paper. Of the 169 patients (all of whom were female)