Predicting Factors of Pain Duration in Patients with Chronic Pain: A Large Population-based Study

Background

Chronic pain is the third main problem of global health and the most common cause of long-term disabilities. The duration that patients suffer from chronic pain is directly proportional to the extent of the suffering and to the amount of health care resources allocated to this problem. There is no research that has studied the risk factors associated with the long pain duration in chronic pain patients.

Methods

We investigated the potential risk factors associated with long pain duration in a population with diverse pain conditions in a cross-sectional study. We used a questionnaire that included a number of potential risk factors including sex, age, marital status, household condition, number of children, employment, education, body mass index (BMI), pain intensity, and the level of anxiety/depression. The data were analyzed by univariable and multivariable linear regression models.

Results

We recruited 780 patients. The analyses showed that age and abnormal BMI had a positive correlation with pain duration.

Conclusions

The risk factors that might be associated with longer pain duration include older age and abnormal BMI.

Effect of supporting membrane on removal of cadmium by the hybrid liquid membrane process

A hybrid liquid membrane process was used to remove cadmium cation from a solution using bis-(2-ethylhexyl) phosphoric acid as the carrier for the first time. Different polyethersulphone supporting membranes were prepared by a phase inversion technique. The prepared membrane could be efficiently used as the supporting membranes for the proposed process. The effects of porosity and pore size of the supporting membrane on removal efficiency were investigated. In addition, the effects of various operating parameters such as carrier concentration in organic phase, pH of feed phase, acid concentration, and temperature on the performance of the process were also investigated. It was found that the maximum flux of cadmium is obtained using the supporting membrane with 84.5% porosity and the pore size of 132 nm. The optimum carrier concentration is 0.2 M, the optimum pH of the feed phase is 6, and the optimum concentration of acid in the stripping phase is 0.6 M.