Nutritional status of vitamin D and dietary intake of key bone health nutrients in Saudi Arabian women : implications for bone health

• Main Author: Khoja, Sawsan Omar
• Published: University of Surrey 2006
• Subjects: 616716.071
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430003

Osteoporosis is a common highly prevalence public health problem affecting both gender in all age stages in worldwide. Little information is known about the bone health and lifestyle characteristics of women living in Middle Eastern countries in general and Saudi Arabia in specific. The complete information and statistical figures of osteoporosis prevalent and vitamin D deficiency among population it has not yet been identified. The strong correlation between dietary intake and bone health has been explored in Western populations but no data are available in Middle Eastern countries. The aims of this study were four fold: (i) to examine the extent of poor bone health in the Saudi population of postmenopausal and premenopausal women; (ii) to investigate the effect of lifestyle factors including physical activity levels and sun-time exposure on bone integrity; (iii) to determine the extent of vitamin D deficiency in the population and the effect of this status on bone mass and calcium/bone metabolism; (iv) to evaluate the dietary quality and quantity in Saudi women and investigate fully the effect of diet on bone health indices. As part of our investigation, a total of 212 Saudi Arabian apparently healthy women were voluntarily participated in this study. A total of 112 postmenopausal and 100 premenopausal women. They were aged 45-60 years and 20-30 years respectively. Bone mineral density (BMD) was determined at the lumbar spine (L2-L4) and femoral neck using dual x-ray absorptiometry (DXA). Calcaneal bone mass was measured by broadband ultrasound attenuation (BUA). All subjects were interviewed concerning their habitual dietary intake, physical activity levels and general lifestyle. Information on dietary intake of each individual was obtained using 3-day estimated food diaries. The amount of food consumed (in grams) for the five food groups was calculated for each subject. Intakes were converted to frequency of consumption (time/d) by dividing food groups by average portion sizes. Using the only existing Food Composition Table for the Middle East, the nutrient values for energy, protein, fat, fibre, calcium, phosphorus, iron, vitamin C, vitamin D and potassium were chosen for the five food groups identified and calculated per 100g. Bone resorption was assessed by measurement of pyridinium crosslinks (PYD) and (DPD) using a second morning urine sample. Bone formation was assessed by bone specific alkaline phosphatase (BSAP) and osteocalcin (OC). Serum 25(OH)D, 1,25(OH)D, PTH, calcium, and phosphorus were measured. Bone health indices indicated a high prevalence of low bone mass in these groups. According to WHO criteria (WHO, 1994), a total of 52% of postmenopausal and 37% of premenopausal women were osteopenic at the lumbar spine. Osteoporotic prevalence was 13% and 2% respectively. Similar results were found for the femoral neck. Physical activity levels were low and exposure to sunlight was low. A significant correlation was found between period of sunlight exposure (min/d) and axial BMD and calcaneal bone mass. The 'quality' of food consumption by Saudi Arabian women does not follow the recommended food guidelines, and the intakes of energy, fibre and potassium in women are lower than those recommended in western population but intakes of phosphorus are somewhat higher. Calcium, vitamin C and iron are around recommended levels. Vitamin D deficiency is highly prevalent in Saudi women, with 78% of women being below the classical threshold of 12ng/ml. A low milk consumption was associated with higher bone resorption in both postmenopausal and premenopausal women which remained significant after adjustment for the key confounding factors of age, weight, height and menopausal status. A low intake of fruit and vegetables and nutrients associated with high fruit and vegetable intake including vitamin C, potassium and estimates of net endogenous acid production were found to be related to poorer indices of bone health. These results are a cause for concern. It indicates that bone health is poor and dietary and lifestyle factors are not favourable to skeletal integrity in Saudi Arabian women.