About the Authors

Malgorzata Pikala

Affiliation Department of Epidemiology and Biostatistics, the Chair of Social and Preventive Medicine of the Medical University of Lodz, Lodz, Poland

Marek Bryla

Affiliation Department of Social Medicine, the Chair of Social and Preventive Medicine of the Medical University of Lodz, Lodz, Poland

Pawel Bryla

Affiliation Department of International Marketing and Retailing, University of Lodz, Lodz, Poland

Irena Maniecka-Bryla

irena.maniecka-bryla@umed.lodz.pl

Affiliation Department of Epidemiology and Biostatistics, the Chair of Social and Preventive Medicine of the Medical University of Lodz, Lodz, Poland

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: IMB MB PB MP. Performed the experiments: MP IMB. Analyzed the data: MP MB PB. Wrote the paper: IMB MP PB MB. Bibliography search and analysis: MB PB.