Refer to exercise 12.44. How could you investigate whether consuming fish at least two times per week causes decreased disease activity in rheumatoid arthritis patients? Describe the design of a study assuming you have 100 rheumatoid arthritis patients in the study.

Exercise 12.44.

A 2017 study reported in the Harvard Health Blog investigated the association between fish consumption and disease activity in 176 rheumatoid arthritis patients (Tedeschi et al. 2017). Frequency of fish consumption was assessed through a questionnaire. Researchers found that participants who consumed fish at least two times per week showed significantly lower disease activity (in other words, less inflammation associated with the disease) than participants who consumed never or less than one time per month. Does this study show that fish consumption causes lower disease activity in rheumatoid arthritis patients? Explain.