Smoking habits were assessed at baseline, and the in 249,190 participants were followed for 3.7 to 3.9 years.

E-cigarette use alone was associated with a 129% higher risk of COPD risk and — specifically among adults ages 30 to 70 — a 39% higher risk of hypertension.

No significant associations were found between e-cigarette use and type 2 diabetes, heart failure, or atherosclerosis.

Combustible cigarette use was associated with a higher risk of essentially all measured outcomes; COPD showed the largest effect (+575% higher risk), followed by atherosclerotic cardiovascular disease (+66% higher risk), heart failure (+50% high risk), hypertension (+20% higher risk), and diabetes (+18% higher risk).

Dual use (using both e-cigarettes and combustible cigarettes) was associated with the highest risks of COPD (+691% higher risk) and atherosclerotic cardiovascular disease (+118% higher risk), with moderately increased risks for hypertension (+21%) and heart failure (+76%), but there was no statistically significant association with type 2 diabetes.

The study results

Condition	E-Cigarette use	Combustible cigarette use	Dual use (e-cig + combustible cigarettes)
COPD	+129% risk	+575% risk	+691% risk
Hypertension	No significant link (+39% risk in analysis of 30–70 year olds)	+20% risk	+21% risk
Type 2 diabetes	No significant link	+18% risk	No significant link
Heart failure	No significant link	+50% risk	+76% risk
Atherosclerotic CVD	No significant link	+66% risk	+118% risk

E-cigarettes aren’t harmless, and combining them with cigarettes makes them even worse Original paper