This is yet another example of my point that statistical significance testing has ruined science
So if someone has a thick neck because their neck is full of fat they will most likely not live as long
But if someone has a thick neck because their neck is strong and muscular that can protect them from a lot of injuries
side note
A higher butt to waist circumfrence ratio is also believed to indicate a lower heart attack risk
Only this study you linked looks at neck circumfrence