Re: Hence usage.
I wouldn't bother with "and" before "so".
Originally Posted by 5jj
I have to slightly disagree with you about the cause/effect situation there. Failure to eat a good healthy diet (to eat properly) can certainly affect your susceptibility to illness, and a lack of vitamin C and antioxidants in the diet can mean you catch colds etc more easily than others. I agree with you that the rather specific "so he caught a cold" is unlikely. "...so he caught lots of colds" would better.
He didn't eat properly so he was prone to illness, particularly in the winter.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.