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Biomedical subjects

P D Saville

Publications and source records attributed to P D Saville.

At least 19 recordsLinked to original sources
PubMed2001

Factors determining calcium intake in elderly women of Appalachia.

BACKGROUND: Although it has been recommended that women aged 65 and older consume at least 1,500 mg of calcium daily, no studies are available that define the factors associated with adequate intake. METHODS: We studied 184 elderly women to determine the relationship between foodstuff calcium consumption and anthropomorphic measurements and numerous life-style changes. RESULTS: The mean foodstuff calcium consumption was 563.4 mg/day, with significantly higher intake noted in women who snacked daily, did not skip meals, drank one or more servings of milk daily, and ate yogurt daily. Dietary calcium intake was also dependent on socioeconomic status and personal attitudes toward milk. CONCLUSIONS: All elderly women in this study underachieved the recommended dietary calcium intake of 1,500 mg/day. Widescale public education to promote more positive attitudes among elderly women is crucial. The evidence from this study recommends calcium supplements with vitamin D for virtually all elderly women.

Aged↗
PubMed1984

Post-menopausal osteoporosis and estrogens. Who should be treated and why.

Estrogen deficiency after menopause results in loss of skeletal calcium and increased risk of bone fractures. Administration to postmenopausal women of a daily dose of 0.625 mg of conjugated equine estrogen, 1 mg estradiol-17 beta, or 0.15 mg ethinyl estradiol prevents these changes. The safety of long-term estrogen administration has not been established by large-scale controlled studies. Therefore, hormone treatment should be reserved for patients with symptoms of estrogen deficiency or for subsets of persons at increased risk of osteoporotic bone fractures. These include fair-skinned or lightweight persons, smokers, heavy drinkers, persons on prolonged corticosteroid therapy, and those with early menopause or rheumatoid arthritis.

Aged↗
PubMed1978

Menopausal changes in calcium balance performance.

Calcium balance as a function of both intake and absorption of calcium fromthe diet was measured 274 times in 168 normal perimenopausal women, and comparisons made between groups of women segregated according to menopausal and estrogen therapy status. As previously reported, there is a statistically significant positive correlation between calcium balance and both calcium intake and calcium absorption. In 207 studies in premenopausal women calcium balance averaged -0.0199 gm/day, whereas in 41 studies in postmenopausal women untreated with estrogen, calcium balance averaged -0.043 gm/day (p less than 0.02). The balance difference was due approximately equally to decreased absorption from the diet and to increased urinary excretion. Twenty-six estrogen-treated postmenopausal women exhibited balance performance indistinguishable from that of the premenopausal group. In 16 women who were studied twice, 5 years apart, and who went through menopause between studies, calcium balance shifted by -0.0307 gm/day (p less than 0.05) as compared with 72 women also studied twice, but without change in menstrual status, in whom mean balance did not change significantly. Calcium intake requirement for zero balance was calculated for both the estrogen-replete and estrogen-deprived groups. Premenopausal and treated postmenopausal women exhibited an intake requirement of 0.990 gm/day Ca, whereas the untreated postmenopausal women had an apparent requirement of 1.504 gm/day (p less than 0.01). We conclude that there is a specific, estrogen-related shift in calcium performance across menopause and that the reason for the positive effect of estrogen on balance and intake requirement is a combination of enhancement of intestinal absorption efficiency and improved renal calcium conservation.

Absorption↗
PubMed1978

Menopausal changes in bone remodeling.

Bone remodeling was measured by a calcium-kinetic method in 151 normal perimenopausal women, and the effect of estrogen status on remodeling level and skeletal balance was determined. Premenopausal women exhibited remodeling rates of 0.337 gm/day Ca for mineral accretion and 0.358 gm/day Ca for mineral resorption. The difference between the two rates (computed skeletal balance) was -0.021 gm/day Ca. Postmenopausal women treated with estrogen in a mean dose of 0.0188 mg equivalents of ethinyl estradiol exhibited values for accretion and resorption (0.332 and 0.351 gm/day Ca), essentially identical with those of the premenopausal group. However, untreated postmenopausal women exhibited remodeling rates of 0.387 gm/day Ca for accretion and 0.425 gm/day Ca for resorption, with a computed skeletal balance of -0.038 gm/day Ca. These values were significantly higher than those of either the premenopausal or treated postmenopausal groups. Paired studies across menopause in 15 of the women demonstrated a rise in remodeling rates virtually identical to that estimated from the differences between groups. Estrogen loss at menopause is thus associated with an apparent partial release from an inhibition of skeletal resorption, and this release is, in whole or part, responsible for the negative skeletal balance shift associated with the postmenopausal years.

Adult↗
PubMed1977

Calcium balance and calcium requirements in middle-aged women.

Calcium balance performance was evaluated in 130 normal perimenopausal women ages 35 to 50, studied on their usual, self-selected dietary calcium intakes. Two distinct balance methods were used, one based on customary intake and output measurements, and the other based on absorption and clearance of two simultaneously administered calcium isotopes. Both methods yielded essentially identical results. Under study conditions as closely approximating normal living as possible, these women averaged -24 and -31 mg Ca/day by the two balance methods (exclusive of unmeasured dermal losses). More significantly, there was a positive correlation between intake and balance, with women on higher self-selected intakes exhibiting more positive balance than women selecting lower intakes. The calcium intake predicted from our data which would be required to produce an average balance of zero was 1.241 g/day. This is significantly in excess of the current recommended dietary allowance for calcium. The implications and significance of this discrepancy are explored in detail.

Absorption↗
PubMed1977

Effect of estrogens and calcium carbonate on bone loss in postmenopausal women.

Sixty postmenopausal women were placed in three groups--control, sex hormone-treated, and CaCO3-treated--and followed for 2 years. Skeletal mass decreased by 1.18%/year in the control group, 0.15%/year in the hormone group, and 0.22%/year in the CaCO3 group by radiogrammetry; and 2.88%/year in the control group, 0.73%/year in the hormone group, and 1.83%/year in the CaCO3 group by photon absorptiometry. The treatment groups differed significantly from the control group except for photon absorptiometry in the CaCO3 group. Bone accretion and resorption decreased in the treatment groups as measured by calcium tracer kinetics, resorption more so than accretion. We conclude that [1] these techniques are sufficiently sensitive to detect age-related bone loss; [2] postmenopausal sex-hormone replacement measurably decreases age-related bone loss by suppressing bone turnover, resorption more than accretion; and [3] calcium supplements produce the same effect but at the dose we used were slightly less effective.

Absorptiometry, Photon↗
PubMed1976

Etidronate disodium in postmenopausal osteoporosis.

Calcium-balance, calcium-kinetic, and physiologic observations were made in 10 osteoporotic patients treated for 6 to 12 mo with disodium etidronate (EHDP) in oral doses of 20 mg/kg/day. Absorption of EHDP averaged 10%, and effective retained dose was approximately 1.6 mg/kg/day. Patient acceptance was excellent, and there were no detectable clinical or biochemical untoward effects of treatment. Serum phosphorus was elevated on average of 1.1 mg/100 ml, and serum calcium, 0.4 mg/100 ml. EHDP reduced bone resorption by about 50% and depressed bone mineralization by almost as much. Both the total miscible calcium pool and its component compartments were smaller on EHDP, presumably because of a combination of interference with bone mineral reactivity and the decrease in mineralization rate. Urine calcium was increased by a small, but highly significant, amount, and gastrointestinal calcium absorption was also significantly increased. Calcium balance shifted slightly but significantly in the positive direction. The magnitude of these changes correlated with the urinary level of EHDP.

Aged↗
PubMed1975

Primary osteoarthrosis of the knee or hip. Prevalence of Heberden nodes in relation to age and sex.

One hundred twenty probands with primary osteoarthrosis of the hip or knee were examined prospectively; there were 194 controls. In addition, 193 patients with hip or knee arthrosis were examined retrospectively. Restriction of rotation on physical examination accurately differentiated arthrotic hips from normal ones. Among women, 38% of the controls and 49% of the probands had Heberden nodes (P more than .1). Their prevalence increased with age. Individuals with multiple arthrosis joints were not older than those with single joint involvement, and they has a similar prevalence of nodes. Of the probands, 14% had arthrosis of both the knee and hip. Of those with bilateral hip arthrosis, 33% had knee arthrosis as well. Heberden nodes are unrelated to osteoarthrosis of the knee or hip. Knee and hip arthroses frequently occur together and remain confined to the initially affected joints. They may have a common cause.

Age Factors↗
PubMed1975

Calcium absorption as a function of calcium intake.

The relationships between the amount of calcium absorbed and the quantity ingested was evaluated in 180 adult humans. Absorption was measured from the concentration ratio of concurrently administered oral and intravenous calcium isotopes. Intake ranged from 0.163 to 7.48 Gm. Ca per day. In 14 subjects, intakes were artificially elevated for purposes of this study. All others were studied at their usual intake levels. Absorption (Ca Abs) was found to follow a curvillnear relationship with intake (Ca-D), and was characterized by the following equation: Ca Abs equals 0.1541 - Ca-D plus 0.3127[exp(-1.0539 - Ca-D)] - Ca-D. The exponential term of this equation provided the major component of total absorption at intakes below 0.8 Gm. per day, but fell to negligible values when intake reached 2 to 3 Gm. per day, above which absorption was characterized by a simple linear function of intake. We found that there was no detectable upper limit to absorption capacity, which, at the 7.48 Gm. intake level, averaged more than 1.0 Gm per day. The observed mathematical description is consistent with the generally recognized inverse relationship between absorption efficiency and intake. At the same time it indicates that a component of absorption is independent of control mechanisms and is related solely to intake. A more general form of the foregoing equation, suggesting provision for other physiological variables such as growth hormone and cortisol, is proposed and discussed.

Acromegaly↗