J7ournal of Epidemiology and Community Health 1996;50:577-78 Short reports Calcium intake among women aged 40-76 in Sweden Karl Michaelsson, Reinhold Bergstrom, Lars Holmberg, Hans Mallmin, Alicja Wolk, Sverker Ljunghall, and the study group MRS SWEA* Calcium is essential for bone strength, but there is no uniform opinion concerning the necessary daily intake of calcium in adult females. Re- commendations range from 500' to 1500 mg/d.' The current recommended daily allowances (RDA) of calcium for adult women in Sweden Department of is 800 mg/d. Orthopaedics, Central Hospital, 721 89 Vasterias, Sweden K Michaelsson Methods: During a four year period, all women Department of aged 40-76 years within a defined area (source Statistics, Uppsala population 90 303) received a food frequency University, Box 513, questionnaire (FFQ) by mail and 74% (ie 75120 Uppsala, 66 671) replied. In the FFQ the women were Sweden R Bergstrom asked to report their usual intake of 60 foods in the previous six months. The frequency re- Cancer Epidemiology, sponses for the foods in the dietary ques- L Holmberg tionnaire were converted into daily nutrient A Wolk intake by using standard portion sizes and the Orthopaedics, computerised data base at the Swedish Food H Mallmin Administration. In addition, the questionnaire included information about age, weight, height, and Internal Medicine, and education. S Ljunghall The responses of those women for whom University Hospital, more than 30 items were missing in the dietary 75185 Uppsala, questionnaire or who had a daily energy intake Sweden below or above three SDs on the logarithmic Correspondence to: scale of the mean energy intake (cut off points Dr K Michadlsson. 417 and 3729 kcal) in the cohort were excluded Accepted for publication as these responses were not reliable. May 1996 judged Jf Epidemiol Commun Health Data on a total of 61 483 women were left for 1996;50:577-78 calculation. Table 1 # coefficients obtained in a multivariate linear regression model with daily intake of calcium as the dependent variable. Age, body mass index (BMI), and educational level are used in categorised form Variable SE(f Constant -56.5 7.1 Energy intake (kcal/d) 0.580* 0.002 Age (y) <45 ref - 45-49 - 5.4t 2.7 50-54 - 16.7* 2.9 55-59 - 11.2* 3.0 60-64 - 9.7k 3.0 65-69 -5.3 3.0 >69 -2.4 4.0 BMI (kg.m2) <18.7 ref - 18.7-23.8 32.7* 6.2 23.8-28.6 45.1* 6.2 >28.6 48.2* 6.5 Educational level: 7- or 9-y compulsory school ref - Upper secondary school 5.3 3.4 University 30.4* 4.1 Other 9.0t 2.9 *p<0.001, tp<0.05, tp<O.O1. The model used in the analysis of the re- lationship between various factors and calcium intake was the standard regression model es- timated by ordinary least squares. Results: Figure 1 shows the cumulative per- centage of daily calcium intake by the par- ticipants. The median intake of calcium was 715 mg/d, the lower quartile limit was 535 mg/d and the upper quartile limit was 920 mg/d. Only 1.5% of the women were estimated to have a dietary calcium intake of more than 1500 mg/d. Energy intake in continuous form and BMI (weight/height2; kg/m2), age, and education in categorised form were used as possible major determinants of calcium intake in a multivariate linear regression model (table 1). Energy intake was strongly and positively related to calcium intake. For every 1000 kcal/d increase in energy intake, there was an increase in calcium intake of 580 mg/d. There was a non-linear association between calcium and age. We found the strong- est decline in intake, compared with younger ages, in the early postmenopausal years of the sixth decade of life. BMI and increasing edu- cational level were positively associated with calcium intake. Discussion: This study indicates that most postmenopausal women in Sweden have de- ficient intake of calcium compared with the current RDA of 800 mg/d, despite the fact that Sweden has one of the highest reported overall intakes of dairy products.3 At a National In- stitutes of Health consensus conference in 1994 it was recommended that postmenopausal 100 90- 80- 70- 60- 50/ 40- / 30 / 20 / I10 0 -- __J ___ i Calcium ine mg &'t Calcium intake (mg/di) Figure 1 Cumulative percentage of mean daily dietary calcium intake. 577