2.1 Design and subjects
A longitudinal cohort non blinded intervention study was conducted from March 2012 to July 2012. In this study, 100 type 2 diabetes out-patients were randomly selected and divided into two groups of intervention and control (50 patients in each group). To control potential confounding factors, the two groups were matched. Although, only 34 and 18 of the 50 patients in the intervention and control group respectively completed the study (Figure 1). Inclusion criteria included; having type 2 diabetes, aged at least 18 years, attending the diabetic clinic, able and willing to perform physical activity for atleast 30 minutes daily during the study period. Those excluded from the study included; very ill type 2 diabetes patients, type 1 diabetes patients, type 2 diabetes patients who were not willing to perform physical activity, and all pregnant diabetic patients. Those patients who were not willing to participate or continue the study were also excluded. The intervention group received nutrition education geared towards promoting dietary diversity, change in the feeding practices, health lifestyle like physical activity, abstinence from alcohol and smoking in addition to the usual care (medication and some rudimental teaching about the dos and don’ts of diabetes) that was provided in the diabetes clinic. This was based on the nutritional recommendations of the world health organization and American Diabetes Association (ADA) . The intervention consisted of two educational sessions, each 30 minutes. The health belief model by Hochbaum et al. (1950) ,which hypothesizes that health-related action depends on sufficient motivation (benefits) to make health issue relevant to consumer was used during nutrition education to promote consumption of a diverse food group diet consisting of Cereals; Vitamin A rich vegetables and tubers; White roots and tubers; Dark green leafy vegetables; Other vegetables; Vitamin A rich fruits; Other fruits; Organ meat; Flesh meat; Eggs; Fish; Legumes, nuts and seeds; Milk and milk products but with observance of non-health oils and fats. The study involved use of various learning objectives. The learning materials included a conversation map for type 2 diabetics, various food samples, food preparation video compact discs, kitchen ware.
Sample size calculation
The statistical equation by Dell (2002) was modified and used to calculate the number of patients who were recruited in the study.
n= (Zα X 2S2)1/2 – Zβ (Se 2 +Sc2) ]2
n = sample size for each group
Zα= Z-value for type I error (e.g.1.96 at 5% level)
Zβ = Z-value for type II error (e.g. 0.84 at 20% level)
Se= Variance estimate of outcome for intervention group receiving nutrition education to promote dietary diversity in addition to the usual care given in the endocrine unit.
Sc= Variance estimate of outcome for control group having only the usual care given in the endocrine unit without the nutrition education promoting dietary diversity.
A similar study called “Diet or diet plus physical activity versus usual care in
Patients with newly diagnosed type 2 diabetes: The Early ACTID randomized controlled trial” was used to get the values of Se of HbA1C equal to 1 and Sc of HbA1C equal to 1.02 (Andrews, 2011).
Values of HbA1C in the above study were used to calculate the sample size as below.
S2 = (Se2+ Sc2)/2 = (1.00)2 + (1.02)2 = 1.0202
n = [ (1.96x 2 x 1.0202)1/2 – 0.84 x 2.0404 ]2
(1 – 1.0404)2
n= [ (3.999184)1/2 – 1.713936]2
That is n= 50 participants
2.2 Data collection
Demographic characteristics of type 2 diabetes patients; gender, age, education, marital status having risk factors of diabetes (smoking, type 2 diabetes mellitus), having a history of diabetes among family members, were completed in a pre-tested questionnaire form. Weight was measured using digital scale with accuracy nearest to 0.1 kg and minimal clothes. Height was also measured by a stadiometer with 0.1 cm accuracy. BMI was calculated by dividing weight (kg) by the square of height (m). These measurements were conducted two times for those who were able to complete the study; once before and once after the intervention period. The intervention group received nutrition education geared towards promoting dietary diversity, change in the feeding practices, health lifestyle like physical activity, abstinence from alcohol and smoking in addition to the usual care that was provided in the diabetes clinic. This was based on the nutritional recommendations of the world health organization and American Diabetes Association (ADA). The intervention consisted of two educational sessions each 30 minutes every week. The IDDS was conducted according to the method described by [8, 9] with some modifications. The DDS of an individual was got by counting number of food groups consumed by an individual divided by 14 and a percentage computed . A Saturday was chosen by consensus because that was the day when patients were to be free and therefore do correct recording of the foods eaten. Mean values of DDS were calculated by adding each individual’s DDS divided by total number of patients in the group. Patients were asked similar questions many times to check for consistency Abrupt community visits were performed to check the filling of dietary diversity score sheets versus real food eaten and following of recommended lifestyle.
2.4 Statistical analyses
Data were analyzed using SPSS (version 21). Student's t test was used to compare the values between the two groups before and after intervention. The mean differences of variables were compared by paired t-test and p-values less than 0.05 were considered significant.