id	keyword
dhrp-64	secondhand
dhrp-64	smoke
dhrp-64	children
dhrp-64	exposure
dhrp-64	health
dhrp-64	smoking
dhrp-64	secondhand smoke
dhrp-64	study
dhrp-64	cause
dhrp-64	doi
dhrp-64	research
dhrp-64	effects
dhrp-64	pmid