What percentage does smoking delay wound healing?

From the Guidelines

Smoking delays wound healing by approximately 30-40% compared to non-smokers. This significant delay is attributed to the detrimental effects of nicotine and carbon monoxide on blood flow, oxygen transport, and immune function, as well as the interference with collagen production 1. The most recent and highest quality study recommends smoking cessation of at least 4 weeks before elective surgery to reduce respiratory and wound-healing complications 1.

Key Factors Affecting Wound Healing

• Nicotine causes vasoconstriction, reducing blood flow to healing tissues and decreasing oxygen and nutrient delivery to the wound site
• Carbon monoxide from cigarette smoke binds to hemoglobin more readily than oxygen does, further reducing oxygen transport to tissues
• Smoking impairs immune function, increases inflammation, and interferes with collagen production, which is essential for wound strength and integrity
• The negative effects on healing are dose-dependent, with heavier smokers experiencing more significant delays

Recommendations for Optimal Wound Healing

• Patients should stop smoking completely at least 4 weeks before elective surgery and continue abstinence throughout the healing process 1
• Even reducing smoking can provide some benefit if complete cessation isn't possible
• Nicotine replacement therapies may be helpful for managing withdrawal symptoms while quitting, though they still contain nicotine which can affect healing, albeit to a lesser extent than smoking 1

From the Research

Delayed Wound Healing due to Smoking

• Smoking is a recognized risk factor for healing complications after surgery, and it decreases tissue oxygenation and aerobic metabolism temporarily 2.
• The inflammatory healing response is attenuated by a reduced inflammatory cell chemotactic responsiveness, migratory function, and oxidative bactericidal mechanisms in smokers 2.
• Smoking has a transient effect on the tissue microenvironment and a prolonged effect on inflammatory and reparative cell functions leading to delayed healing and complications 2.
• Research has shown that smoking attenuates epidermal healing and may enhance extracellular matrix degradation, with one week after wounding, transepidermal water loss (TEWL) being 17.20 g/cm(2) hour in smokers and 13.89 g/cm(2) hour in never smokers (p<0.01) 3.
• Studies have found that three months of abstinence from smoking does not restore epidermal healing, whereas 4 weeks of abstinence normalizes suction blister MMP-8 levels, suggesting sustained impaired wound healing in smokers and potential reversibility of extracellular matrix degradation 3.

Percentage Delay in Wound Healing

• Although the exact percentage delay in wound healing due to smoking is not specified in the studies, research has effectively linked smoking with delayed wound healing and healing complications 4, 5, 6.
• It is generally accepted that smoking impairs wound healing, with local and systemic responses to smoking having deleterious effects on wound healing 6.
• Reducing fibroblast activity and keratinocyte migration are some of the ways cigarette smoking affects wound healing at a cellular level, leading to delayed healing 5.