Turns out the increased mortality is almost exclusively amongst those with high-school diploma or less, and linked to suicide, drug overdose, mental health issues, and other stress-associated disorders.
Rather than being a sign of too much welfare, it's more a sign of people falling out of the social contract, leading to destitution and despair.
The American Prospect:
The declining health of middle-aged white Americans may also shed light on the intensity of the political reaction taking place on the right today. The role of suicide, drugs, and alcohol in the white midlife mortality reversal is a signal of heightened desperation among a population in measurable decline. We are not talking merely about “status anxiety” due to rising immigrant populations and changing racial and gender relations. Nor are we talking only about stagnation in wages as if the problem were merely one of take-home pay. The phenomenon Case and Deaton have identified suggests a dire collapse of hope, and that same collapse may be propelling support for more radical political change. Much of that support is now going to Republican candidates, notably Donald Trump. Whether Democrats can compete effectively for that support on the basis of substantive economic and social policies will crucially affect the country’s political future.