Introduction:
Ferritin has been implicated in body physiology and pathology. Smoking cigarettes (Cg) alters ferritin metabolism. Waterpipe (Wp) smoking has recently reemerged as a global epidemic and is linked to the most devastating diseases. However, the effect of smoking Wp on ferritin is not known. Therefore, the current study compared plasma ferritin in adolescents smoking Cg, Wp, both (CgWp) versus never smoked.

Material and methods:
Self-reported smoking status and plasma ferritin levels were obtained from 849 boys (n = 470) and girls (n = 379) in the 7th–10th grade (age range = 13–17 years).

Results:
The ANCOVA revealed a main effect for gender (p < 0.000) and smoking status (p < 0.02) without an interaction effect (p > 0.9). Post-hoc analysis showed greater plasma ferritin in the adolescents smoking Wp (p < 0.03) and CgWp (p < 0.004) versus never smoked. Gender-stratified ANCOVA showed a main effect for smoking status in the boys (p < 0.02) and girls (p < 0.03). Additional comparisons among the boys showed greater plasma ferritin in the Wp (p < 0.006) and CgWp (p < 0.008) smoking groups versus never smoking, without differences (p > 0.5) between Wp and CgWp smoking. Another subgroup comparison showed greater plasma ferritin in the girls smoking Cg (p < 0.02) and CgWp (p < 0.02) versus never smoking, without a difference (p > 0.3) between Cg and CgWp smoking.

Conclusions:
The results indicate that ferritin is elevated in adolescent smokers, particularly the boys smoking Wp and CgWp and in the girls smoking Cg and CgWp.