Giving up cigarettes may increase a patient's risk of type 2 diabetes, researchers say.

    In a longitudinal study, quitters had a 73% greater risk of the disease than never-smokers, Hsin-Chieh Yeh, PhD, of Johns Hopkins University, and colleagues reported online in the Annals of Internal Medicine.

    Yeh and her colleagues wrote that quitters "experienced relatively more adverse changes in their metabolic profile and an increased risk for incident diabetes that peaked within three years of quitting but was still observable six years after quitting."

    "Weight gain after smoking cessation explained the increased risk in those quitters," Yeh told MedPage Today.

    "Also, those who smoked more and gained the most weight had the highest short-term risk" of developing diabetes.

    Increased inflammation may also play a role, Yeh added.

    Cigarette smoking is an established risk factor for type 2 diabetes, but little was known about the effects of smoking cessation on diabetes risk.

    So the researchers analyzed longitudinal data from the prospective cohort Atherosclerosis Risk in Communities （ARIC） Study of 10,892 middle-age adults who did not have diabetes at baseline, between 1987 and 1989.

    Smoking was assessed at baseline and incident diabetes was measured by fasting glucose assays.

    Over nine years of follow-up, 1,254 patients developed type 2 diabetes.

    The researchers found a graded relationship between pack-years of smoking and incidence of type 2 diabetes, which increased from 13.3 per 1,000 person-years in those who never smoked to 18.5 per 1,000 person-years in the highest tertile of pack-years.

    Risk of diabetes was increased 1.42-fold among those in the highest tertile of smokers （more than 30 pack-years）, compared with never-smokers （95% CI 1.20 to 1.67）.

    Those who smoked for fewer than 13 pack-years had a nonsignificant 9% increased risk, and those with 14 to 30 pack-years had a 1.38-fold increased risk （95% CI 1.18 to 1.61）.

    The researchers then looked at the relationship between smoking cessation and diabetes risk. In the first three years of follow-up, 380 patients quit smoking.

    The new quitters had more significant increases in weight, waist circumference, and fasting glucose level, as well as a small but statistically significant decrease in leukocyte count compared with never-smokers （P<0.001）.

    After adjusting for potential confounders, the researchers found that new quitters had the highest odds of type 2 diabetes （HR 1.73, 95% CI 1.19 to 2.53）.

    They were followed by continuing smokers （HR 1.31, 95% CI 1.04 to 1.65） and former smokers （HR 1.22, 95% CI 0.99 to 1.50）.

    The researchers said the findings regarding continuing smokers were "surprising," but noted it may be that nicotine and its metabolites exert anti-inflammatory effects.

    In an analysis of long-term risk after quitting, the highest risk occurred in the first three years （HR 1.91, 95% CI 1.19 to 3.05） and gradually decreased to zero at 12 years.

    "Weight gain, in terms of prevention and intervention, is the most straightforward target for people who are ready to quit and those who have already quit," Yeh said.

    She said doctors and patients should be aware of the potential problems and couple smoking cessation with strategies for diabetes prevention and early detection.

    "Lifestyle counseling in terms of diet and physical activity and maybe other, more aggressive types of weight management are needed," Yeh said. "And [physicians should] check up on glucose level more frequently as another way for early detection."

    She said there's also some evidence that nicotine replacement therapy is helpful in terms of weight control after quitting.

    "Of course, the basic message is, don't even start smoking," Yeh said.

    Some of the study's limitations included self-reported data, telephone interviews at some of the time points, possible under-representation of smokers at later follow-up, and an observational study design, which cannot prove causality.

    研究人員稱，戒煙可增加2型糖尿病的發生風險。

    一項縱向研究發現，戒煙者發生糖尿病的風險比不吸煙者高73%.約翰霍普金斯大學Hsin-Chieh Yeh博士及其同事將該研究發表在《內科學年鑒》在線版上。

    Yeh博士和同事稱，戒煙者會發生相對不良的代謝變化，且糖尿病發病風險增加，該風險在戒煙后的3年內最高，并在戒煙后6年持續存在。

    "戒煙引起的體重增加可能是糖尿病風險增加的原因。"Yeh 說。

    "而且，那些吸煙多，體重增加多的人們短期發生糖尿病的風險最高。"

    炎性反應的增加也起到一定作用，Yeh補充說。

    吸煙是明確的2型糖尿病危險因素，但戒煙對糖尿病發生風險的影響尚不清楚。

    因此研究者分析了前瞻性社區內大樣本動脈粥樣硬化風險研究（ARIC）的縱向數據，該研究在1987年至1989年間登記了10892名尚未患糖尿病的中年人。

    研究評估了受試者基線時的吸煙情況，并以空腹血糖值評定糖尿病的發病。

    隨訪9年以上，1254名受試者發生了糖尿病。

    研究者發現，年吸煙量與2型糖尿病的發生呈正相關，從不吸煙者每1000病人年的13.3增加到年吸煙量最大者1000病人年的18.5.

    與不吸煙者相比，嚴重吸煙者（每年超過30包）的糖尿病風險增加1.42倍（95% CI 1.20-1.67）.

    每年吸煙少于13包的人群，糖尿病發生風險增加9%,而每年14-30包，風險則增加1.38倍（95% CI 1.18-1.61）.

    研究者也觀察了戒煙和糖尿病風險的關系。在隨訪的前3年，共380名患者戒煙。

    與不吸煙者相比，新近戒煙者會出現明顯的體重增加、腰圍增大及空腹血糖增高，且出現輕度但已達統計學意義的白細胞計數減少（P<0.001）.

    校正了潛在的混雜因素后，研究者發現，新近戒煙者發生2型糖尿病的幾率最高（風險比1.73,95% CI 1.19-2.53）.

    其次是持續吸煙者（風險比1.31,95% CI 1.04-1.65）和曾經吸煙者（風險比1.22,95% CI 0.99-1.50）.

    研究者稱，該結果中持續吸煙者的糖尿病發生風險出乎意料，但指出這可能是尼古丁及其代謝物產生了抗炎作用。

    戒煙后的長期風險分析中，前3年的風險最高（風險比1.91,95% CI 1.19-3.05）,此后直到12年風險逐漸減少至沒有。

    "無論預防還是干預，體重增加均是準備戒煙和已經戒煙的人們最直觀的指標。"Yeh說。

    她提醒醫生和患者應意識到這一潛在問題，并對戒煙者進行糖尿病預防和早期干預。

    "飲食和運動等生活方式的調整，積極控制體重都是必須的。"Yeh說，"而且為了早期發現，醫生們應經常檢測戒煙者的血糖水平。"

    她還指出，目前也有證據表明尼古丁替代療法有助于戒煙后的體重控制。

    "當然，最根本的是，不要嘗試吸煙。"Yeh說。

    該研究也存在局限性，包括數據的采集來源于自我報告，一些時間點的訪視通過電話完成，后期隨訪中吸煙者的代表不足，以及這是一項觀察性研究，不能證實因果關系。