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.

    研究人员称，戒烟可增加2型糖尿病的发生风险。

    一项纵向研究发现，戒烟者发生糖尿病的风险比不吸烟者高73%.约翰霍普金斯大学Hsin-Chieh Yeh博士及其同事将该研究发表在《内科学年鉴》在线版上。

    Yeh博士和同事称，戒烟者会发生相对不良的代谢变化，且糖尿病发病风险增加，该风险在戒烟后的3年内最高，并在戒烟后6年持续存在。

    "戒烟引起的体重增加可能是糖尿病风险增加的原因。"Yeh 说。

    "而且，那些吸烟多，体重增加多的人们短期发生糖尿病的风险最高。"

    炎性反应的增加也起到一定作用，Yeh补充说。

    吸烟是明确的2型糖尿病危险因素，但戒烟对糖尿病发生风险的影响尚不清楚。

    因此研究者分析了前瞻性社区内大样本动脉粥样硬化风险研究（ARIC）的纵向数据，该研究在1987年至1989年间登记了10892名尚未患糖尿病的中年人。

    研究评估了受试者基线时的吸烟情况，并以空腹血糖值评定糖尿病的发病。

    随访9年以上，1254名受试者发生了糖尿病。

    研究者发现，年吸烟量与2型糖尿病的发生呈正相关，从不吸烟者每1000病人年的13.3增加到年吸烟量最大者1000病人年的18.5.

    与不吸烟者相比，严重吸烟者（每年超过30包）的糖尿病风险增加1.42倍（95% CI 1.20-1.67）.

    每年吸烟少于13包的人群，糖尿病发生风险增加9%,而每年14-30包，风险则增加1.38倍（95% CI 1.18-1.61）.

    研究者也观察了戒烟和糖尿病风险的关系。在随访的前3年，共380名患者戒烟。

    与不吸烟者相比，新近戒烟者会出现明显的体重增加、腰围增大及空腹血糖增高，且出现轻度但已达统计学意义的白细胞计数减少（P<0.001）.

    校正了潜在的混杂因素后，研究者发现，新近戒烟者发生2型糖尿病的几率最高（风险比1.73,95% CI 1.19-2.53）.

    其次是持续吸烟者（风险比1.31,95% CI 1.04-1.65）和曾经吸烟者（风险比1.22,95% CI 0.99-1.50）.

    研究者称，该结果中持续吸烟者的糖尿病发生风险出乎意料，但指出这可能是尼古丁及其代谢物产生了抗炎作用。

    戒烟后的长期风险分析中，前3年的风险最高（风险比1.91,95% CI 1.19-3.05）,此后直到12年风险逐渐减少至没有。

    "无论预防还是干预，体重增加均是准备戒烟和已经戒烟的人们最直观的指标。"Yeh说。

    她提醒医生和患者应意识到这一潜在问题，并对戒烟者进行糖尿病预防和早期干预。

    "饮食和运动等生活方式的调整，积极控制体重都是必须的。"Yeh说，"而且为了早期发现，医生们应经常检测戒烟者的血糖水平。"

    她还指出，目前也有证据表明尼古丁替代疗法有助于戒烟后的体重控制。

    "当然，最根本的是，不要尝试吸烟。"Yeh说。

    该研究也存在局限性，包括数据的采集来源于自我报告，一些时间点的访视通过电话完成，后期随访中吸烟者的代表不足，以及这是一项观察性研究，不能证实因果关系。