Life expectancy is going up due to a variety of factors: better trauma care, better vaccination regimes, better sanitation, better nutrition, some better treatments (some amazingly so).
Nevertheless, a large fraction of medical screens and procedures does not improve average life expectancy when people actually try to measure their impact. Intensive end-of-life care does not improve life expectancy when similarly measured.
In terms of citations, see http://papers.ssrn.com/sol3/papers.cfm?abstract_id=161308 at least for the end-of-life effects. Also see http://www.theatlantic.com/magazine/archive/2010/11/lies-dam... and http://www.nejm.org/doi/full/10.1056/NEJMoa1000678 and http://www.overcomingbias.com/2010/06/beware-active-placebos... and http://papers.nber.org/papers/W16011 and the RAND health insurance study. For a start, at least.
