Rechargeable

Here, they find a correlation between e-cigarette use and higher and more sustained levels of smoking. But because this is a cross-sectional study, they cannot determine which came first. In other words, what is the direction of the causal relationship? Does the e-cigarette use precede, and cause, the smoking? Or does the smoking precede, and cause, the e-cigarette use?

LAST：Hot selling Variable Voltage vamo v5 ecig Full Mechanical Mod 2014 vamo v5 ecig by kingberry |NEXT：2014 New Product Panzer Mod Clone Black&Stainless Steel Body Panzer Mechanical Mod