BMC Public Health 2009, 9:166 http://www.biomedcentral.com/1471-2458/9/166 The Homeostasis Model Assessment (HOMA) is used to estimate insulin resistance and beta-cell function [29]. HOMA-IR is computed as follows: fasting insulin (μU/ml) × fasting glucose (mmol/L)/22.5. HOMA-B is calculated using the following formula: 20 × fasting insulin (μU/ ml)/fasting glucose (mmol/L) – 3.5. Microalbuminuria is defined as a urine Albumin:Creati- nine Ratio (ACR) ≥ 2.5 – 25 mg/mmol in men and ≥ 3.5 – 25 mg/mmol in women [30]. Treatment targets for blood lipids are values of fasting total cholesterol below 4.5 mmol/L and fasting LDL cholesterol below 2.5 mmol/ L [31]. Physical measurements Patients above 60 years of age perform a 6 minutes walk test in an indoor unobstructed corridor. They are instructed by a physical therapist to walk the 30 meter from one end to the other at their own pace, as many times as possible, in the permitted time. After 6 minutes, the total distance walked (in meter) is measured. The 6 minute walk test is a useful measure of functional capac- ity, targeted at older people and people with moderate-to- severe physical impairment and has well known reference equations [32,33]. For patients below 60 years of age physical fitness is meas- ured by using a submaximal cycle ergometer aerobic fit- ness test (Astrand-Rhyming Cycle Ergometer Test). Patients cycle on an ergometer at a constant workload for 6 minutes. Heart rate is measured every minute, and based on the steady state heart rate, VO2 max (correlation to VO2 max approximately 0.85–0.9) is determined from a nom- ogram [34,35]. All participants perform a strength test that involves the determination of the maximum weight that can be lifted 5 repetitive times by arms and legs while maintaining proper form (5RM test) [36]. Self reported daily physical activity (average hours per week in the last 6 months) is divided into: 1) Transportation exercise: walking and bicycling and 2) Training exercise: jogging, training in a fitness centre, swimming, bicycling, etc[36]. Quality of life questionnaires Short Form Health Survey (SF-36) is a multi-purpose, short-form health survey with 36 questions. It yields an 8- scale profile of functional health and well-being scores as well as psychometrically-based physical and mental health summary measures and a preference-based health utility index. The SF-36 has proven to be useful in surveys of general and specific populations, comparing the rela- tive burden of diseases, and has been used to differentiate the health benefits produced by a wide range of different treatments [37]. A higher score on SF-36 indicates an improvement in Quality of Life. Diabetes Symptom Checklist – Revised (DSC-R) is a self- report questionnaire of 34 questions grouped into 8 symptom subscales measuring the occurrence and per- ceived burden of diabetes-related symptoms [38]. It has been described to be valid, reliable and responsive to change and to be the only scale that appears to evaluate physical functioning in T2DM patients in a broad, com- prehensive manner [39]. A lower score on DSC-R indi- cates an improvement in Quality of Life. Sample size considerations and statistical methods The size of the study population is based on the primary outcome measure HbA1c and is estimated on the basis of the results of two meta-analyses relating to education and exercises in T2DM patients [8,14]. According to power cal- culation, an absolute difference of 0.7% in HbA1c between the groups (power 0.9, significance level 0.05) may be detected with 80 patients in each group. This cal- culation is based on a standard deviation of the HbA1c- value of 1.3 from larger population studies [40]. Neither patients nor study personnel are blinded to treat- ment assignment. The study statistician carrying out the data analysis on the primary and secondary outcomes will be blinded and will not have any contact with the patients. Descriptive statistics (means ± SD, or median and inter- quartile ranges, as appropriate) will be used to describe the study sample with regards to baseline characteristics. The analysis will be performed according to the intention- to-treat principles using the statistical software SAS 9.1. Comparisons of primary and secondary outcomes between the two groups will be analyzed by values after the intervention at the 6 months follow-up visit, and 12 and 24 months after baseline, using appropriate paramet- ric tests for variables fulfilling the normal distribution cri- teria or appropriate non-parametric tests for variables not fulfilling the normal distribution criteria. Sensitivity anal- yses will be carried out with adjustment for possible con- founders. When relevant the change in outcomes from baseline to 6, 12 and 24 months follow-up will be assessed. The proportion of patients reaching the recom- mended goals for glycated haemoglobin, blood pressure and lipids will be compared in a sub-analysis. Statistical significance is set at P < 0.05. Ethics The study will be conducted according to the principles of the Helsinki declaration. The Danish National Committee on Biomedical Research Ethics and the Danish Data Pro- tection Agency have approved the study protocol. 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