Estimation of insulin resistance in non-diabetic normotensive Saudi adults by QUICKI, HOMA-IR and modified QUICKI: a comparative study

Identification of insulin resistance [IR] in the general population is important for developing strategies to reduce the prevalence of non-insulin-dependent diabetes mellitus [NIDDM]. We used the original and a modified version of the Quantitative Insulin Sensitivity Check Index [QUICKI, M-QUICKI], and the Homeostasis Model Assessment of Insulin Resistance [HOMA-IR] to divide non-diabetic normotensive adults into high-[HIR] and low-insulin-resistant [LIR] subgroups to investigate similarities and differences in their characteristics. Three hundred fifty-seven healthy adults aged 18-50 years were recruited randomly from health centers in Jeddah in a cross-sectional study design. Anthropometric and demographic information was taken. Insulin, glucose, lipid profile and free fatty acid were determined in fasting blood samples. M-QUICKI, HOMA-IR and QUICKI were calculated. Reported cut-off points were used to identify HIR subjects, who were then matched for age and sex to others in the study population, resulting in 3 HIR and 3 LIR subgroups. Two hundred nine subjects satisfied the selection criteria. M-QUICKI correlated significantly [P=.01] with HOMA-IR and QUICKI values. Increased adiposity was the common characteristic of the three HIR subgroups. HIR subgroups identified using M-QUICKI [97 subjects] and HOMA [25 subjects], but not QUICKI [135 subjects], had statistically different biochemical characteristics compared to corresponding LIR sub-groups. Adiposity, but not sex, is a risk factor for IR in the studied population. Further studies are needed to choose the most appropriate index for detecting IR in community-based surveys

Dietary macronutrient intake of Saudi males and its relationship to classical coronary risk factors

To investigate whether the dietary intake of energy; macronutrients; and fiber differ between age groups, racial groups and socio-economic classes among males from the Western province of Kingdom of Saudi Arabia [KSA]. Data were collected from 303 male subjects, aged 15-80 years. They were selected randomly from King Abdul-Aziz University Hospital, Jeddah, KSA from October 2001 to November 2003 and grouped according to their age into 3 groups. The subjects were asked to complete a questionnaire concerning their demographic characteristics, health history, lifestyle, and dietary habits. Energy and carbohydrates intake fell with age [p<0.05]. Total dietary carbohydrates and fat intake were similar for all groups when expressed as a percentage of energy intake. The percentage energy as protein increased with age [p<0.05]. Mean cholesterol intake was high for all groups, but fell with age group [p<0.0001]. Saturated fat and monounsaturated fat intake, expressed as percentage energy intake were both high, whereas polyunsaturated fat intake was low. The youngest group had the highest percentage energy provided by saturated fatty acid [p<0.001], and the lowest percentage energy as polyunsaturated fatty acid [p<0.05] compared to the other groups. The intake of fibre rose with age was significantly higher in the older group [p<0.05]. Diet consumed by urban dwellers in KSA appears to have resulted in an imbalance of macronutrient intake among all sectors of the population. This problem can only be averted by raising public awareness and the development of appropriate population-specific nutritional guidelines

Serum 25 - hydroxy cholecalciferal in infants and preschool children in the western region of Saudi Arabia. Etiological factors

Low vitamin D status has been frequently reported among Saudi subjects of all ages. No attempt has been made to relate this status to dietary intake or to diseases leading to malabsorption, for example diarrhea. This study was performed to investigate the various factors leading to low vitamin D status, and their relative importance in infants and preschool children. Nine hundred and thirty-five healthy subjects aged 4-72 months were selected randomly form the Jeddah area of the Kingdom of Saudi Arabia. Medical history, time and frequency of exposure to sunlight and dietary intake were recorded. Blood samples were obtained form 739 subjects for the determination of 25-hydroxy cholecalciferol. The Subjects were divided into 5 age groups. The mean +/- standard deviation and other statistical parameters for serum 25-hydroxy cholecalciferol were calculated. Mean +/- standard deviations of exposure time and vitamin D intake were calculated, and subjects divided according to the adequacy of their intake. Age had no effect on the mean serum 25-hydroxy cholecalciferol [p=0.63]. Mean dietary intake of the vitamin increased initially [p<0.05], decreased in the next group [p<0.005], then remained constant. There was significant correlation between serum level and dietary intake of the vitamin. No exposure to sunlight was noted in the youngest group. Low serum levels were associated mainly with repeated diarrheal attacks. This was the same in the next group. The mean exposure time in the 3rd group increased significantly [p<0.001]. Low serum levels were found in subjects with low exposure time plus either or both of low dietary intake and repeated attacks of diarrhea. Increased mean exposure time [p<0.0005], and decreased incidence of repeated diarrheal attacks were found in the next age group with low serum levels noted in subjects with low exposure time and low dietary intake. In the oldest age group, mean exposure time increased further [p<0.0005], and low levels were found in subjects with low exposure time [mainly girls]. Diet was the major source of the vitamin in subjects <12 months of age, and hence low levels were associated with frequent diarrheal attacks. A decrease in dietary intake, and more dependence on endogenous vitamin synthesis was apparent in older children, leading to low vitamin status in ones with low dietary intake and inadequate exposure to sunlight

Effects chromium supplementation on glucose tolerance and lipid profile

To investigate chromium status of the adult population in the western region of Saudi Arabia and the possibility of using serum chromium status measurement as indicator of this status. The effect of chromium supplement on glucose tolerance and lipid profile was studied in 44 normal, free living adults. 200mg chromium/day as CrCL3 or a placebo was given in a double blind cross-over study, with 8 weeks experimental periods. Fasting, 1 hour and 2 hour post glucose challenge [75g of glucose] glucose, serum fructosamine, total cholesterol, high-density lipoprotein-cholesterol, triglycerides, chromium and dietary intakes were estimated at the beginning and the end of each stage. Mean serum chromium increased significantly after supplement [P<.001] indicating proper absorption of the element. Supplement did not effect the total cholesterol, however, the mean high-density lipoprotein-cholesterol level was significantly increased [P<.001], the mean triglycerides levels significantly decreased [P<.001], and the mean fructosamine level significantly decreased [P<.05]. In addition, chromium supplement effected 1 hour and 2 hour post glucose challenge glucose levels in subgroups of subjects with 2 hour glucose level > 10% above or below fasting level and significantly differing to it [P<.05 in both cases], by decreasing or increasing them significantly [P<.05 in all cases] so that the 2 hour mean became not significantly different to the fasting mean. Since no significant changes in weight, dietary intake or habits were found, and placebo had no effect, all noted biochemical changes were attributed to chromium. Improved glucose control, and lipid profile following chromium supplement suggests the presence of low chromium status in the studied population. However, serum chromium could not be recommended for use as an indicator of chromium status as subjects with widely varying levels responded favorably to the chromium supplement