Osteoporosis is a public health problem. It is a disease that is present for a long period without signs, before resulting in the clinical sign, i.e. fracture(s). Osteoporosis can be prevented in part and there are treatments. Among other lifestyle factors, the dietary intake of calcium is important when working with preventive intervention towards individuals and groups. For dietary assessment, an instrument adjusted for Swedish circumstances is needed.
The aims of the thesis are to design and validate an instrument estimating calcium intake (I), to estimate calcium intake from dairy products and supplements in an adult Swedish population, and to explore associations between calcium intake and some lifestyle factors and between calcium intake and bone mineral density (II).
Two questionnaires were prepared, one short (A), containing questions about dairy products and supplements, and another more extensive (B), with questions on a wide variety of food products. The questionnaires were validated with dietary history as the gold standard. Two age groups of women, 20-30 and 50-60 years, were included (n=467) (I). A randomised sample of 15% women and men aged 20-79 years in two communities answered a questionnaire (n= 1510). Forearm bone mineral density was measured in a subsample of this group (n=448) (II).
We found questionnaire A to be sufficient when discriminating individuals with low calcium intake from individuals with sufficient calcium intake (I). The mean calcium intake from dairy products was well attained (878 mg/day) although the range was wide. However, 12% in the 20-30 years age group and 31% in the 70- 79 years age group did not meet the recommended daily intake. Associations were found between calcium intake and residence and also physical activity. There was a tendency towards an association between calcium intake and forearm bone mineral density. No other associations with lifestyle factors were observed (II).
ln osteoporosis intervention work there is every reason to strive towards meeting the recommended daily intake for all individuals, and our quick and cheap food frequency questionnaire could be of value.
Linköping: Linköpings universitet , 2005. , 37 p.
food frequency questionnaire, validation, calcium intake, osteoporosis, lifestyle factors