Lightening the fracture load: growing evidence suggests many older New Zealanders would benefit from more vitamin D.
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Aged↗
Biomedical subjects
A Goulding
Publications and source records attributed to A Goulding.
Lactose malabsorption and rate of bone loss in older women.
OBJECTIVES: to study the prevalence of lactose malabsorption with increasing age and to determine whether lactose malabsorbers consume less dietary calcium, have lower bone mineral density or display faster bone loss than lactose absorbers. DESIGN: 80 healthy Caucasian women aged 40-79 years (20 per decade) were studied for 1 year. METHODS: breath hydrogen exhalation was measured for 3 after a 50 g oral lactose challenge. Bone density was assessed in the radius, femoral neck, lumbar spine and total body by dual energy x-ray absorptiometry and dietary calcium intake was estimated by 4-day diet records and food-frequency questionnaires. RESULTS: lactose malabsorption rose with age (15% in those aged 40-59 years versus 50% in those aged 60-79; P < 0.01). Malabsorbers aged 70-79 years consumed significantly less calcium than lactose absorbers of this age (P < 0.05). Baseline total body calcium values were lower in lactose malabsorbers (n=26) than in lactose absorbers (n=54) but age-adjustment eliminated this difference. Bone change (% per year) was correlated with dietary calcium intake at the femoral neck and trochanter (P < 0.05) but was not statistically greater in malabsorbers than in absorbers. CONCLUSIONS: the ability to absorb lactose declines in the 7th decade. This may contribute to decreased dietary intakes of milk products and calcium in elderly women. However, lactose malabsorption without reduction in calcium intake has little effect on bone mineral density or the rate of bone loss.
Adult↗
Plasma leptin values in relation to bone mass and density and to dynamic biochemical markers of bone resorption and formation in postmenopausal women.
After the menopause it has been noted that heavier women conserve bone better than those with lower body weight. The protective effect of obesity on bone mass has been ascribed to a high body fat content. The present study of 54 postmenopausal women was undertaken to determine whether circulating plasma levels of leptin, the newly described hormone produced in adipocytes, were correlated with age-adjusted total body bone mineral content (BMC) or bone mineral density (BMD), or with dynamic biochemical markers of bone resorption or of bone formation. Leptin values were strongly correlated with all measures of adiposity (P < 0.001). Age-adjusted values for BMC and BMD, respectively, were also positively correlated (P < 0.001) with body weight (r = 0.643, r = 0.502), total fat mass (r = 0.557, r = 0.510) and with plasma leptin concentrations (r = 0.480, r = 0.551), confirming a positive relationship between fat mass and bone mass. By contrast, no significant correlations were observed between plasma leptin and dynamic markers of bone resorption (urinary deoxypyridinoline/creatinine r = -0.105, hydroxyproline/creatinine r = -0.193) or formation (plasma osteocalcin r = 0.103). Because there was no evidence for an association between ciculating plasma levels of leptin and biochemical markers of either osteoclastic or osteoblastic activity we conclude it is unlikely that circulating leptin plays any significant direct role in controlling bone cell activity. Our results do not support the hypothesis that leptin mediates the bone-sparing effects of obesity.
Aged↗
Validation of a short food frequency questionnaire to assess calcium intake in children aged 3 to 6 years.
OBJECTIVE: To assess the validity of a short calcium food frequency questionnaire (FFQ) for use in young children. DESIGN: Calcium intake from an estimated 4 d diet record (4DDR) was compared with the calcium intake from a 35 item FFQ specifically designed to assess habitual calcium intake and previously validated for adult women. SUBJECTS: Forty-one girls and 26 boys aged 3-6 y recruited by advertisement for studies of nutrition and bone health. RESULTS: Mean (s.d.) calcium intakes were 798 mg (271) and 942 mg (419) for the 4DDR and FFQ respectively, (r = 0.52). Mean difference (s.d. of difference) in calcium intake between the two methods was 144 mg (355), showing that the FFQ may estimate calcium intakes 565 mg below to 854 mg above diet record values. 84% of subjects when classified by the 4DDR fell into the same or adjacent quartiles when classified by the FFQ. Only two subjects were classified in extreme quartiles for the two methods. The FFQ correctly identified 68% of children with recorded intakes less than 800 mg. CONCLUSIONS: The short calcium FFQ tended to overestimate actual calcium intakes in young children, and would not be appropriate for determining calcium intake of individuals. However, the FFQ demonstrated good ability to classify subjects into extremes of calcium intake. Moreover, the predictive value of the FFQ in identifying children with intakes below the current recommended intake of 800 mg was reasonably high (79%).
Adult↗
DEXA: a practical and accurate tool to demonstrate total and regional bone loss, lean tissue loss and fat mass gain in paraplegia.
Persons with spinal cord injury lose lean tissue mass and bone but gain body fat. There is a need to quantify the magnitude of these changes in body composition because there are associated skeletal and cardiovascular health risks. We have compared total body and regional (lower limb) differences in body composition in a group of males with paraplegia and in healthy able-bodied males matched for age, and height using dual energy X-ray absorptiometry. Although patients and controls had similar body mass indices, significant reductions in lean tissue mass (16% less) and bone (12% less) were observed in those with spinal cord injury. Group differences were even more pronounced in the lower limb. DEXA also revealed large increases in fat mass in subjects who did not look obese, total fat mass being 47% higher in the paraplegic group. We suggest that DEXA provides a simple and practical means to quantify both whole body and regional changes in body composition associated with spinal cord injury.
Absorptiometry, Photon↗
Body mass index, waist girth, and waist-to-hip ratio as indexes of total and regional adiposity in women: evaluation using receiver operating characteristic curves.
Receiver operating characteristic (ROC) curves were constructed to assess the value of body mass index (BMI) as a screening measure for total adiposity and to examine waist-to-hip ratio (WHR) and waist circumference as measures of central fat distribution. Body fat reference measurements were determined by dual-energy X-ray absorptiometry (DXA). The study population comprised 96 healthy white women aged 16-80 y. A positive reference test was defined as a result at or above the 75th percentile for our study population for all DXA measurements. Sensitivity and specificity were calculated at several percentile cutoffs for BMI, WHR, and waist girth. The areas under the ROC curves were calculated to compare the relative ability of each anthropometric technique to correctly classify subjects according to the reference measurement for that technique. BMI (our 75th percentile = 27.3) performed well as a screening measure of total adiposity, correctly identifying 83% of subjects with a high body fat mass while misclassifying only eight subjects [four false-negatives (subjects with high fat mass who were in the low BMI category) and four false-positives (subjects with a low fat mass who were in the high BMI category)]. The screening performance of WHR (our 75th percentile = 0.81) was lower, accurately categorizing 58% of subjects while misclassifying 28 subjects. By contrast, waist circumference (our 75th percentile = 86.9 cm) was significantly better than WHR at screening for regional fat distribution, accurately classifying 83% of subjects and misclassifying eight subjects (P < 0.05). We conclude that BMI and waist circumference provide simple yet sensitive methods for the estimation of total and central adiposity in groups of adult women.
Absorptiometry, Photon↗
Plasma leptin in relation to regional body fat in older New Zealand women.
BACKGROUND: Leptin is the protein product of the obesity (ob) gene and is produced in adipose tissue. Plasma leptin values are highly correlated with total body fat mass but less is known concerning relationships of leptin with regional adiposity. AIM: To investigate associations between leptin and dual energy X-ray absorptiometry (DEXA) measures of regional body fat deposition in older New Zealand women. METHODS: Body composition was measured in 80 women aged 40 to 79 years (20 in each decade) using DEXA. Height and weight were measured by conventional anthropometry. Plasma leptin concentrations were assayed by radioimmunoassay. RESULTS: Leptin was strongly correlated (p < 0.001) with weight (r = 0.751), body mass index (r = 0.782), total fat mass (r = 0.854) and % fat mass (r = 0.813). A statistical model with trunk fat (kg) and leg fat (kg) as the independent variables showed that trunk fat accounted for 72.1% of the variance in plasma leptin with leg fat explaining only a further 1.6% of the variance. No relationships were found between leptin and age, height, lean tissue mass or menopausal status (p > 0.05). CONCLUSIONS: We conclude that trunk fat explains more of the variance in circulating leptin concentrations than leg fat, suggesting that the propensity to leptin resistance may be increased in women with higher central adiposity.
Absorptiometry, Photon↗
Bone mineral density in girls with forearm fractures.
In childhood, the most common site of fracture is the distal forearm. To determine whether young girls with these fractures have low bone density more commonly than fracture-free controls, we measured bone density at the radius, spine, hip, and whole body and total body bone mineral content, lean tissue mass, and fat mass by dual-energy X-ray absorptiometry in 100 Caucasian girls aged 3-15 years with recent distal forearm fractures and 100 age- and gender-matched controls. Bone density (age-adjusted ratios of all cases:controls with 95% confidence intervals) was lower in cases at the ultradistal radius 0.963 (0.930-0.996), 33% radius 0.972 (0.945-0.999), lumbar spine 0.945 (0.911-0.980), hip trochanter 0.952 (0.918-0.988), and total body 0.978 (0.961-0.995). Moreover, osteopenia (defined as Z score below -1), was more common in cases than controls (p < 0.05) in the forearm, spine, and hip, with one third of fracture cases having low spinal density. Odds ratios (95% confidence intervals) for low bone density were: ultradistal radius, 2.2 (1.1-4.6); lumbar spine, L2-L4, 2.6 (1.3-4.9); and femur trochanter, 2.0 (1.0-3.9). Fracture patients aged 8-10 years weighed more (mean +/- SD) than age-matched controls (37.2+/-8.0 kg vs. 32.5+/-6.6 kg, p < 0.01) while older patients reported lower current and past calcium intakes than matched controls (p < 0.05). We conclude that low bone density is more common throughout the skeleton in girls with forearm fractures than in those who have never broken a bone, supporting the view that low bone density may contribute to fracture risk in childhood.
Adolescent↗
Low vitamin D status is common among elderly Dunedin women.
AIMS: To review vitamin D status and the relationship of serum 25-hydroxyvitamin D levels to hip bone mineral density in a group of healthy elderly women living independently in their own homes in Dunedin. METHODS: Thirty-eight elderly subjects (> 70 years of age) were studied. Serum levels of 25-hydroxyvitamin D (25(OH)D) were measured by radioimmunoassay in summer and winter. Femoral neck bone mineral density was measured by dual x-ray energy absorptiometry. RESULTS: Hip density was correlated with serum 25(OH)D levels at study entry. In summer, 10 of 38 patients (26.3%) had serum 25(OH)D levels below the reference range for healthy adults (40-185 nmol/L). Six patients subsequently withdrew from the study. In winter, 22 of the remaining 32 women (68.8%) had serum 25(OH)D values below the reference range. Subjects with low 25(OH)D values were given halibut oil tablets (400 IU vitamin D3 per day) to improve their serum 25(OH)D levels. CONCLUSIONS: Vitamin D deficiency is common among elderly women with a high risk of fracture who live in southern New Zealand. This is most marked in the winter months. Vitamin D replacement is cheap and effective and should be considered in patients over 70 years of age who have a high risk of fracture and who live in temperate climates.
Absorptiometry, Photon↗
Women with past history of bone fracture have low spinal bone density before menopause.
AIMS: Recent work from our laboratory has demonstrated that young girls with bone fractures have low spinal bone density more often than girls who have never fractured. This study was undertaken to determine whether adult women approaching menopause who have any past history of fracture have lower spinal density than women who have never fractured. METHODS: A lifetime fracture history was taken from all premenopausal women (n = 59) enrolled in a clinical trial examining the effect of menopause on cardiac risk. Bone mineral density of the lumbar spine was measured at study entry by dual energy x-ray absorptiometry (Lunar DPX-L) and results from patients with and without fracture were compared. RESULTS: Women with a previous history of fracture (n = 23) had significantly lower bone density (6% less) than the women who had never broken a bone (n = 36). CONCLUSIONS: We conclude that women who report a previous history of fracture, either as young adults or in childhood, should be targeted for perimenopausal screening for osteoporosis since they are likely to have lower bone density and a greater risk of future fracture than women with no past history of fracture.
Absorptiometry, Photon↗
Gender differences in body fat content are present well before puberty.
To determine whether gender differences in body fat could be detected in prepubertal children using dual energy X-ray absorptiometry (DEXA), body composition was measured in 20 healthy boys aged 3-8 y matched for age, height and weight with 20 healthy girls. Although boys and girls did not differ in age, height, weight, body mass index (BMI) or bone mineral content, the boys had a lower percentage of body fat (13.5 +/- 5.1 vs 20.4 +/- 6.1%, P < 0.01), a lower fat mass (3.2 +/- 2.0 vs 4.9 +/- 3.1 kg, P < 0.01), and a higher bone-free lean tissue mass (18.6 +/- 4.3 vs 17.0 +/- 3.5 kg, P < 0.01) than the girls. Girls had approximately 50% more body fat than the boys. This is the first DEXA study to show that boys aged 3-8 y have less body fat than girls of similar age, height and weight. Thus, this technology demonstrates that significant gender differences in body composition are evident, well before the onset of puberty.
Absorptiometry, Photon↗
In vivo antiviral activity and pharmacokinetics of (-)-cis-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine in woodchuck hepatitis virus-infected woodchucks.
The (-) enantiomer of cis-5-fluoro-1l-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine [(-)-FTC)], a substituted oxathiolane compound with anti-hepatitis B virus activity in vitro, was assessed for its efficacy in woodchucks with naturally acquired woodchuck hepatitis virus (WHV) infection. Pharmacokinetics and in vitro anabolism were also determined. (-)-FTC was anabolized to the 5'-triphosphate in a dose-related fashion, reaching a maximum concentration at about 24 h in cultured woodchuck hepatocytes. Following administration of a dose of 10 mg/kg of body weight intraperitoneally (i.p.), the clearance of (-)-FTC from plasma was monoexponential, the terminal half-life was 3.76 +/- 1.4 h, and the systemic clearance was 0.12 +/- 0.06 liters/h/kg. The antiviral efficacy of (-)-FTC in the woodchuck model was assessed by quantitation of serum WHV DNA levels and by WHV particle-associated DNA polymerase activity at two dosages, 30 and 20 mg/kg given i.p. twice daily (b.i.d.), respectively. The level of WHV DNA in serum was reduced 20- to 150-fold (average, 56-fold) in the 30-mg/kg-b.i.d. treatment group and 6- to 49-fold (average, 27-fold) in the 20-mg/kg-b.i.d. treatment group. Viral DNA polymerase levels diminished accordingly. One week after treatment was discontinued, WHV levels returned to pretreatment levels in both studies. These animals were biopsied before and following treatment with 30 mg of (-)-FTC per kg. Their livers were characterized by a mild increase in cytoplasmic lipid levels, but this change was not associated with altered liver enzyme levels. Serum chemistry and hematology results were within the normal ranges for all treated animals. We conclude that (-)-FTC is a potent antihepadnaviral agent and that it has no detectable toxic effects in woodchucks when given for up to 25 days. Further development of (-)-FTC as an anti-hepatitis B virus therapy for patients is warranted.
Animals↗
More exercise, less central fat distribution in women.
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Absorptiometry, Photon↗
Effects of hysterectomy on bone in intact rats, ovariectomized rats, and ovariectomized rats treated with estrogen.
To determine whether the uterus plays any role in mediating the ability of estrogen to conserve bone in the rat, eight groups of animals (n = 8) with their skeletons labeled with 45Ca were studied. Rats were ovariectomized (OVX), hysterectomized (Hyst), or given sham operations (Sham) and then pair-fed a low-hydroxyproline casein diet for 4 weeks. The groups were treated orally with 17 beta-estradiol (E2) or vehicle, and serial measurements of biochemical markers of bone breakdown were made in weeks 1, 2, and 4. The femur density was measured by dual-energy X-ray absorptiometry (DXA), and skeletal calcium and 45Ca content were determined chemically. Final total body calcium values (mg) in the eight treatment groups were (means +/- SD): Sham, 2573 +/- 179; Sham + E2, 2635 +/- 159; Hyst, 2537 +/- 151; Hyst + E2, 2410 +/- 151; OVX, 2189 +/- 146; OVX + E2, 2559 +/- 172; OVX/Hyst, 2138 +/- 132; and OVX/Hyst + E2, 2460 +/- 140. Ovariectomy raised biochemical markers of bone resorption (urinary 45Ca, hydroxyproline, and deoxypyridinoline), lowered DXA bone mineral density, and reduced total body calcium and 45Ca content in both Hyst and Sham-Hyst animals (p < 0.001), whereas E2 treatment prevented these changes. Hysterectomy did not impair the ability of E2 to conserve bone in OVX rats. Thus, we conclude that estrogen-mediated induction of growth factors from uterine tissue does not play an essential role in mediating the bone-conserving actions of estrogen in the rat.
Animals↗
Changing femoral geometry in growing girls: a cross-sectional DEXA study.
In elderly women, a long hip axis length has been shown to increase the risk of hip fracture. However, to date, few measurements of hip geometry have been reported in children and adolescents. The present cross-sectional dual-energy X-ray absorptiometry (DEXA) study of 200 girls aged 3-16 years was undertaken to determine at what age adult hip geometry is achieved and to examine possible influences of anthropometry and body composition on the development of femur axis length (FAL) and femur width (FW) during growth. Adult values for FAL and FW were achieved by age 15 years. Age, height, lean tissue mass, total body bone mineral content (BMC), weight, FW, neck of femur bone mineral density (BMD), and fat were each strongly associated with FAL (p < 0.001), the highest correlations being with age (r = 0.917) and height (r = 0.906). However, after adjusting for age and height, only lean tissue mass, weight, and fat mass remained significantly associated with FAL, suggesting that bone mineral accrual does not influence variance in FAL. Our results also suggested that fat mass and weight per se tended to have greater influence on FW than on FAL in age- and height-adjusted data. Twin studies indicate that 20% of adult hip axis length is associated with environmental factors. We therefore conclude that any environmental effects of physical activity or nutrition on hip geometry must occur before early teen-age years.
Absorptiometry, Photon↗
Regional body fat distribution in relation to pubertal stage: a dual-energy X-ray absorptiometry study of New Zealand girls and young women.
A cross-sectional study of 140 healthy, non-obese women and growing girls aged 8-27 y was undertaken to examine changes in total-body and regional fat and fat-free lean tissue mass by Tanner stage of pubertal development with dual-energy X-ray absorptiometry. Absolute fat mass and absolute fat-free lean tissue mass were higher at successive Tanner stages (1 through 5) but the proportional increase was greater for fat: total fat mass (kg) was about threefold higher in Tanner stage 5 than in stage 1 (P < 0.001), whereas lean tissue mass (kg) in Tanner stage 5 was about double that in stage 1 (P < 0.001). Furthermore, although the regional distribution of lean tissue mass in the trunk and legs remained fairly constant at different pubertal stages, the regional distribution of fat was altered significantly, becoming more central and less peripheral. Trunk fat (as a percentage of total body fat) was significantly higher at stage 5 than at stage 1 (P < 0.001). In the whole population, body mass index was positively correlated with trunk fat (r = 0.662, P < 0.0001) and negatively with leg fat (r = -0.457, P < 0.0001). We conclude that girls accumulate a higher proportion of their total adult fat mass than of their total adult lean tissue mass during puberty, and that regional fat patterns become more android and less gynoid with maturity.
Absorptiometry, Photon↗
The effect of oral vanadyl sulfate on body composition and performance in weight-training athletes.
The effects of oral vanadyl sulfate (VOSO4) (0.5 mg/kg/day) on anthropometry, body composition, and performance were investigated in a 12-week, double-blind, placebo-controlled trial involving weight-training volunteers. Performance was assessed in the treatment (VS) and placebo (P) groups using 1 and 10 repetitions maximum (RM) for the bench press and leg extension. Thirty-one subjects completed the trial, with 2 VS subjects withdrawing because of apparent side effects. There were no significant treatment effects for anthropometric parameters and body composition during the trial. Both groups had significant improvements in performance but the only significant effect of treatment was a Treatment x Time interaction in the 1 RM leg extension (p = .002), which could have arisen because the VS group had a lower performance at baseline in this test. It was concluded that oral vanadyl sulfate was ineffective in changing body composition in weight-training athletes, and any modest performance-enhancing effect requires further investigation.
Absorptiometry, Photon↗
Regional body fat distribution in New Zealand girls aged 4-16 years: a cross-sectional study by dual energy X-ray absorptiometry.
OBJECTIVE: To measure total body fat content and its regional distribution within the body (head, arms, legs and trunk) in young girls and adolescents in relation to age and body mass index (BMI). DESIGN: Cross-sectional observational study. SUBJECTS: 196 healthy Caucasian girls aged 4-16 years living in an urban town in the South Island of New Zealand. MEASUREMENTS: Body weight, height and BMI. Total body fat mass (kg) and the regional distribution of this fat (measured by dual energy X-ray absorptiometry). RESULTS: All the measured variables, including total and % fat mass were higher in older age groups. Regional distribution of fat differed, with older girls having a higher proportion of their body fat in the trunk and a smaller proportion of their body fat in the heat than younger girls. BMI was positively correlated with % trunk fat (r = 0.700) and negatively correlated with % leg fat (r = -0.465). Girls with higher levels of adiposity (> 75th percentile for BMI) stored more fat in the trunk and correspondingly less in the legs than girls with lower adiposity (< or = 75th percentile for BMI) at five of the six age groups (P < 0.05). CONCLUSION: It is concluded that body fat mass increases and shows a more central distribution in young girls as they grow older. Increasing adiposity as determined by BMI is associated with an increase in fat deposition in the trunk and a decrease in the legs.
Absorptiometry, Photon↗