Associations : LED street-lighting and breast cancer (new study)

Some things might help in preventing cancer. Some things might be found to be causing cancer.  And yet other things might be ‘associated’ with cancer – that’s to say they might occur along with rising cancer rates, and yet may, or may not, be a cause. For example, could there be a previously overlooked statistical association between breast cancer mortality rates in Los Angeles County and the recent introduction of high-efficiency LED street-lighting in the area? A new paper for the Journal of Environmental Economics and Management finds, surprisingly perhaps, that there is.

“[…] the LED program was associated with increased breast cancer mortality in LA County after a latency period. This result was robust to several validity checks.”

– explains Professor Benjamin Jones, of the Department of Economics at the University of New Mexico, US, who has discovered the association. The reasons behind a possible breast cancer association remain unclear – but the professor suggests that the blue-rich spectrum of the LED light might warrant further investigation. Reminding us however that :

“ […] the results from this work should be interpreted as being consistent with a causal spillover health effect story, if in fact one does exist, but are not proof of causation nor a demonstration of causal mechanisms by which LED light is linked to health.“

See: ‘Spillover health effects of energy efficiency investments: Quasi-experimental evidence from the Los Angeles LED streetlight program’ in Journal of Environmental Economics and Management, Volume 88, March 2018, Pages 283-299. A full copy of which may be found here.

BONUS: Those interested in the implications of statistical associations might also like to see ‘Tim Harford’s guide to statistics in a misleading age’ in the Financial Times, 8th Feb 2018 (Note: if paywalled, a summary can be found here)