Biomedical subjects

H de Waard

Publications and source records attributed to H de Waard.

9 recordsLinked to original sources

PubMed1990

Habitual dietary calcium intake and cortical bone loss in perimenopausal women: a longitudinal study.

During an 8-year follow-up study, the effect of habitual dietary calcium intake on cortical bone loss in 154 healthy perimenopausal women was examined. Dietary calcium intake, determined by the cross-check dietary history method, and cortical bone mineral content of the radius were measured annually. Habitual dietary calcium intake was calculated as the mean of the estimated daily dietary calcium intake during the follow-up period. The women were classified according to their habitual calcium intake: those with an intake below 800 mg/day (n = 28), between 800 and 1350 mg/day (n = 95), and above 1350 mg/day (n = 31). The results show a continuous significant loss of cortical bone in all groups, amounting yearly to 1.3 +/- 0.25, 1.5 +/- 0.10, and 1.9 +/- 0.23% (mean +/- SE) for the groups with a low, medium, and high habitual calcium intake, respectively (P less than 0.01). The differences among the three groups did not reach statistical significance (P = 0.11). Body mass index was found to be positively correlated with the negative changes in cortical bone mineral density (r = 0.32, P less than 0.01), even after adjustments had been made for confounding factors. It is concluded that a habitual calcium intake exceeding 800 mg/day (the current Recommended Daily Allowance for adults) is ineffective in preventing cortical bone loss during early menopause. Body mass index is of major importance for the perimenopausal bone loss.

Body Mass Index↗

PubMed1990

Relation of axial bone mass to habitual calcium intake and to cortical bone loss in healthy early postmenopausal women.

A group of 60 healthy early postmenopausal women participating in an ongoing study on the effect of habitual calcium intake on the rate of cortical bone loss at the radius, were subjected to additional skeletal measurements at the lumbar spine and femoral neck. The women were between 58 and 64 years of age, and 3 to 10 years postmenopausal. No correlations were found between habitual calcium intake (range 560 to 2580 mg/day) and either bone mineral content of the radius, the lumbar spine and the femoral neck, or spine deformity index. Body mass index was found to be positively correlated with bone mass indices of the radius (decrease of BMD and BMD) and femoral neck (BMC), but not with of the lumbar spine (BMC, BMD and SDI), even after adjustments had been made for confounding factors. Although the rate of cortical bone loss at the radius correlated significantly with bone mineral content of lumbar spine and femoral neck, the error in predicting bone mass of the lumbar spine or the femoral neck from longitudinal measurements of cortical bone at the radius was high. The rate of cortical bone loss did not correlate with the spine deformity index. We conclude that in healthy women in early menopause, the bone mineral content of both the appendicular and the axial skeleton are not influenced by habitual calcium intake. A higher body mass index has a protective effect on the appendicular skeleton but appears to be less protective to the axial skeleton. Longitudinal measurements of cortical bone mass are of limited value to predict bone density of the appendicular and axial skeleton.

Absorptiometry, Photon↗

PubMed1986

Design and data quality of a mixed longitudinal study to elucidate the role of dietary calcium and phosphorus on bone mineralization in pre-, peri-, and postmenopausal women.

The study design and data quality control of an ongoing study (10 yr duration) in a few hundred women are presented. Good variables with respect to their longitudinal usefulness are: body weight, body height, and span-width. Reasonable variables are the bone parameters of the radius (BMC, BW, and BMC/BW). Poor variables are: dietary calcium and phosphorus intake, dietary calcium-to-phosphorus ratio, urinary calcium-to-creatinine ratio, urinary sodium-to-creatinine ratio, hematocrit, serum alkaline phosphatase activity, serum gamma-GT activity, and serum parathyroid-hormone concentration. Bad variables are: urinary phosphorus-to-creatinine ratio, urinary hydroxyproline-to-creatinine ratio, creatinine clearance, hemoglobin, MCHC, serum calcium, serum ionized calcium, serum phosphorus, serum total protein, serum albumin, and serum creatinine. In conclusion, it is possible to relate bone loss to food intake and to changes in anthropometric variables on an individual basis. However, quantification of the metabolic process is not possible.

Anthropometry↗

PubMed1986

Oral calcium and blood pressure: a controlled intervention trial.

In a double-blind, placebo-controlled trial with 58 normotensive female students, the effect of oral-calcium supplementation (1500 mg Ca++/day for 6 wk) on diastolic and systolic blood pressure was studied while students were consuming a low-calcium diet (500 mg Ca++/day) by restricting the intake of dairy products. Results show that, in both the calcium- and placebo-supplemented groups, blood pressure values decreased slightly and no effect of oral-calcium supplementation on blood pressure could be demonstrated. In addition, at baseline neither systolic nor diastolic blood pressure correlated with habitual calcium intake. Diastolic but not systolic blood pressure correlated significantly with body mass index (r = 0.31, p = 0.01). It is concluded that oral-calcium supplementation for 6 wk does not influence blood pressure in young, healthy normotensive females consuming low-calcium diet.

Administration, Oral↗

PubMed1980