title: The long-term effect of lifestyle interventions to prevent diabetes in the China Da Qing Diabetes Prevention Study: a 20-year follow-up study.
abstract: BACKGROUND
  Intensive lifestyle interventions can reduce the incidence of type 2 diabetes in people with impaired glucose tolerance, but how long these benefits extend beyond the period of active intervention, and whether such interventions reduce the risk of cardiovascular disease (CVD) and mortality, is unclear. We aimed to assess whether intensive lifestyle interventions have a long-term effect on the risk of diabetes, diabetes-related macrovascular and microvascular complications, and mortality.
  
  
  METHODS
  In 1986, 577 adults with impaired glucose tolerance from 33 clinics in China were randomly assigned to either the control group or to one of three lifestyle intervention groups (diet, exercise, or diet plus exercise). Active intervention took place over 6 years until 1992. In 2006, study participants were followed-up to assess the long-term effect of the interventions. The primary outcomes were diabetes incidence, CVD incidence and mortality, and all-cause mortality.
  
  
  RESULTS
  Compared with control participants, those in the combined lifestyle intervention groups had a 51% lower incidence of diabetes (hazard rate ratio [HRR] 0.49; 95% CI 0.33-0.73) during the active intervention period and a 43% lower incidence (0.57; 0.41-0.81) over the 20 year period, controlled for age and clustering by clinic. The average annual incidence of diabetes was 7% for intervention participants versus 11% in control participants, with 20-year cumulative incidence of 80% in the intervention groups and 93% in the control group. Participants in the intervention group spent an average of 3.6 fewer years with diabetes than those in the control group. There was no significant difference between the intervention and control groups in the rate of first CVD events (HRR 0.98; 95% CI 0.71-1.37), CVD mortality (0.83; 0.48-1.40), and all-cause mortality (0.96; 0.65-1.41), but our study had limited statistical power to detect differences for these outcomes.
  
  
  CONCLUSIONS
  Group-based lifestyle interventions over 6 years can prevent or delay diabetes for up to 14 years after the active intervention. However, whether lifestyle intervention also leads to reduced CVD and mortality remains unclear.
authors.affiliation: Department of Endocrinology, China-Japan Friendship Hospital, Beijing, China. guangwei_li@medmail.com.cn
authors.forename: Guangwei
authors.initials: G
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Jinping
authors.initials: J
authors.lastname: Wang
authors.forename: Edward W
authors.initials: EW
authors.lastname: Gregg
authors.forename: Wenying
authors.initials: W
authors.lastname: Yang
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Gong
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Hongliang
authors.initials: H
authors.lastname: Li
authors.forename: Yayun
authors.initials: Y
authors.lastname: Jiang
authors.forename: Yali
authors.initials: Y
authors.lastname: An
authors.forename: Ying
authors.initials: Y
authors.lastname: Shuai
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Jingling
authors.initials: J
authors.lastname: Zhang
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Thompson
authors.forename: Robert B
authors.initials: RB
authors.lastname: Gerzoff
authors.forename: Gojka
authors.initials: G
authors.lastname: Roglic
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Hu
authors.forename: Peter H
authors.initials: PH
authors.lastname: Bennett
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000401:mortality; D002681:China / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008019:Life Style; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D013997:Time Factors