[timr]

Yes. Also, the survey response rate was the biggest difference between groups (54% vs 47%), which could easily explain the observed differences. The confidence intervals cross 1.0 for nearly all reported IRR values.

For those who don't know how to interpret medical evidence, this study is very weak.

[usgroup]

Those response rates are fairly awful with two groups that are markedly different. Seems very likely that they’d self-select on the face of it especially if they knew what the research question was.