Here's a thought on why it's so hard to think about trade-offs between health and happiness: people think about different risk very differently depending on the situation. An increased chance of death from 4% to 5% this year is very different from an increase from 1% to 3%. Or consider:
Fishermen (think "Deadliest Catch") have a 1.1% chance of dying on-the-job each year (granted that's not really an increased risk of dying by quite 1.1%) and they make about $13 an hour, which is next to no premium over many other unskilled laborers. But suppose they make $5 more per hour and work 2000 hours a year more than someone at Wal-Mart. That means they'd being compensated for the risk by $10,000.
Now consider that you've been impressed into the English army for an amphibious landing in France. Your risk is dying that day is 2% (ignore non-fatal injuries) and they say they'll let you go after they establish a beachhead. How much would you be willing to escape 2% chance of sudden death? If they above scenario is any guide (or this valuation from speed limits) you should be willing to pay about $20,000 but no more.