Caryl Nowson

Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis

BACKGROUND Whether calcium supplementation can reduce osteoporotic fractures is uncertain. We did a meta-analysis to include all the randomised trials in which calcium, or calcium in combination with vitamin D, was used to prevent fracture and osteoporotic bone loss. METHODS We identified 29 randomised trials (n=63 897) using electronic databases, supplemented by a hand-search of reference lists, review articles, and conference abstracts. All randomised trials that recruited people aged 50 years or older were eligible. The main outcomes were fractures of all types and percentage change of bone-mineral density from baseline. Data were pooled by use of a random-effect model. FINDINGS In trials that reported fracture as an outcome (17 trials, n=52 625), treatment was associated with a 12% risk reduction in fractures of all types (risk ratio 0.88, 95% CI 0.83-0.95; p=0.0004). In trials that reported bone-mineral density as an outcome (23 trials, n=41 419), the treatment was associated with a reduced rate of bone loss of 0.54% (0.35-0.73; p<0.0001) at the hip and 1.19% (0.76-1.61%; p<0.0001) in the spine. The fracture risk reduction was significantly greater (24%) in trials in which the compliance rate was high (p<0.0001). The treatment effect was better with calcium doses of 1200 mg or more than with doses less than 1200 mg (0.80 vs 0.94; p=0.006), and with vitamin D doses of 800 IU or more than with doses less than 800 IU (0.84 vs 0.87; p=0.03). INTERPRETATION Evidence supports the use of calcium, or calcium in combination with vitamin D supplementation, in the preventive treatment of osteoporosis in people aged 50 years or older. For best therapeutic effect, we recommend minimum doses of 1200 mg of calcium, and 800 IU of vitamin D (for combined calcium plus vitamin D supplementation).

Fruit and vegetable consumption and stroke: meta-analysis of cohort studies

BACKGROUND Increased consumption of fruit and vegetables has been shown to be associated with a reduced risk of stroke in most epidemiological studies, although the extent of the association is uncertain. We quantitatively assessed the relation between fruit and vegetable intake and incidence of stroke in a meta-analysis of cohort studies. METHODS We searched MEDLINE, EMBASE, the Cochrane Library, and bibliographies of retrieved articles. Studies were included if they reported relative risks and corresponding 95% CIs of stroke with respect to frequency of fruit and vegetable intake. FINDINGS Eight studies, consisting of nine independent cohorts, met the inclusion criteria. These groups included 257,551 individuals (4917 stroke events) with an average follow-up of 13 years. Compared with individuals who had less than three servings of fruit and vegetables per day, the pooled relative risk of stroke was 0.89 (95% CI 0.83-0.97) for those with three to five servings per day, and 0.74 (0.69-0.79) for those with more than five servings per day. Subgroup analyses showed that fruit and vegetables had a significant protective effect on both ischaemic and haemorrhagic stroke. INTERPRETATION Increased fruit and vegetable intake in the range commonly consumed is associated with a reduced risk of stroke. Our results provide strong support for the recommendations to consume more than five servings of fruit and vegetables per day, which is likely to cause a major reduction in strokes.

Increased consumption of fruit and vegetables is related to a reduced risk of coronary heart disease: meta-analysis of cohort studies

Increased consumption of fruit and vegetables has been shown to be associated with a reduced risk of coronary heart disease (CHD) in many epidemiological studies, however, the extent of the association is uncertain. We quantitatively assessed the relation between fruit and vegetable intake and incidence of CHD by carrying out a meta-analysis of cohort studies. Studies were included if they reported relative risks (RRs) and corresponding 95% confidence interval (CI) of CHD with respect to frequency of fruit and vegetable intake. Twelve studies, consisting of 13 independent cohorts, met the inclusion criteria. There were 278 459 individuals (9143 CHD events) with a median follow-up of 11 years. Compared with individuals who had less than 3 servings/day of fruit and vegetables, the pooled RR of CHD was 0.93 (95% CI: 0.86–1.00, P=0.06) for those with 3–5 servings/day and 0.83 (0.77–0.89, P<0.0001) for those with more than 5 servings/day. Subgroup analyses showed that both fruits and vegetables had a significant protective effect on CHD. Our meta-analysis of prospective cohort studies demonstrates that increased consumption of fruit and vegetables from less than 3 to more than 5 servings/day is related to a 17% reduction in CHD risk, whereas increased intake to 3–5 servings/day is associated with a smaller and borderline significant reduction in CHD risk. These results provide strong support for the recommendations to consume more than 5 servings/day of fruit and vegetables.

Should older people in residential care receive vitamin D to prevent falls? Results of a randomized trial.

Objectives: To determine whether vitamin D supplementation can reduce the incidence of falls and fractures in older people in residential care who are not classically vitamin D deficient.

Serum vitamin D and falls in older women in residential care in Australia

Objectives: To determine the prevalence of vitamin D deficiency in older people in residential care and the influence that the level of vitamin D may have on their incidence of falls.

BMI and all-cause mortality in older adults: a meta-analysis

BACKGROUND Whether the association between body mass index (BMI) and all-cause mortality for older adults is the same as for younger adults is unclear. OBJECTIVE The objective was to determine the association between BMI and all-cause mortality risk in adults ≥65 y of age. DESIGN A 2-stage random-effects meta-analysis was performed of studies published from 1990 to 2013 that reported the RRs of all-cause mortality for community-based adults aged ≥65 y. RESULTS Thirty-two studies met the inclusion criteria; these studies included 197,940 individuals with an average follow-up of 12 y. With the use of a BMI (in kg/m2) of 23.0-23.9 as the reference, there was a 12% greater risk of mortality for a BMI range of 21.0-21.9 and a 19% greater risk for a range of 20.0-20.9 [BMI of 21.0-21.9; HR (95% CI): 1.12 (1.10, 1.13); BMI of 20.0-20.9; HR (95% CI): 1.19 (1.17, 1.22)]. Mortality risk began to increase for BMI >33.0 [BMI of 33.0-33.9; HR (95% CI): 1.08 (1.00, 1.15)]. Self-reported anthropometric measurements, adjustment for intermediary factors, and exclusion of early deaths or preexisting disease did not markedly alter the associations, although there was a slight attenuation of the association in never-smokers. CONCLUSIONS For older populations, being overweight was not found to be associated with an increased risk of mortality; however, there was an increased risk for those at the lower end of the recommended BMI range for adults. Because the risk of mortality increased in older people with a BMI <23.0, it would seem appropriate to monitor weight status in this group to address any modifiable causes of weight loss promptly with due consideration of individual comorbidities.

Vitamin D and health in adults in Australia and New Zealand: a position statement

The prevalence of vitamin D deficiency varies, with the groups at greatest risk including housebound, community‐dwelling older and/or disabled people, those in residential care, dark‐skinned people (particularly those modestly dressed), and other people who regularly avoid sun exposure or work indoors. Most adults are unlikely to obtain more than 5%–10% of their vitamin D requirement from dietary sources. The main source of vitamin D for people residing in Australia and New Zealand is exposure to sunlight. A serum 25‐hydroxyvitamin D (25‐OHD) level of ≥ 50 nmol/L at the end of winter (10–20 nmol/L higher at the end of summer, to allow for seasonal decrease) is required for optimal musculoskeletal health. Although it is likely that higher serum 25‐OHD levels play a role in the prevention of some disease states, there is insufficient evidence from randomised controlled trials to recommend higher targets. For moderately fair‐skinned people, a walk with arms exposed for 6–7 minutes mid morning or mid afternoon in summer, and with as much bare skin exposed as feasible for 7–40 minutes (depending on latitude) at noon in winter, on most days, is likely to be helpful in maintaining adequate vitamin D levels in the body. When sun exposure is minimal, vitamin D intake from dietary sources and supplementation of at least 600 IU (15 μg) per day for people aged ≤ 70 years and 800 IU (20 μg) per day for those aged > 70 years is recommended. People in high‐risk groups may require higher doses. There is good evidence that vitamin D plus calcium supplementation effectively reduces fractures and falls in older men and women.

A co-twin study of the effect of calcium supplementation on bone density during adolescence

The effect of calcium supplementation on bone mineral density (BMD) was evaluated in female twin pairs aged 10–17 years with a mean age of 14 years. Forty-two twin pairs (22 monozygotic, 20 dizygotic; (including one monozygotic pair from a set of triplets) completed at least 6 months of the intervention: 37 pairs to 12 months and 28 pairs to 18 months. BMD was measured by dual-energy X-ray absorptiometry (DXA). In a double-blind manner, one twin in each pair was randomly assigned to receive daily a 1000 mg effervescent calcium tablet (Sandocal 1000), and the other a placebo tablet similar in taste and appearance to the calcium supplement but containing no calcium. Compliance (at least 80% tablets consumed), as measured by tablet count, was 85% in the placebo group and 83% in the calcium group over the 18 months of the study, on average increasing dietary calcium to over 1600 mg/day. There was no within-pair difference in the change in height or weight. When the effect of calcium supplementation on BMD was compared with placebo at approximately 6, 12 and 18 months, it was found that there was a 0.015±0.007 g/ cm2 greater increase in BMD (1.62±0.84%) at the spine in those on calcium after 18 months. At the end of the first 6 months there was a significant within-pair difference of 1.53±0.56% at the spine and 1.27±0.50% at the hip. However, there were no significant differences in the changes in BMD after the initial effect over the first 6 months. Therefore, we found an increase in BMD at the spine with calcium supplementation in females with a mean age of 14 years. The greatest effect was seen in the first 6 months; thereafter the difference was maintained, but there was no accelerated increase in BMD associated with calcium supplementation. The continuance of the intervention until the attainment of peak bone mass and follow-up after cessation of calcium supplementation will be important in clarifying the optimal timing for increased dietary calcium and the sustained, long-term effects of this intervention.

Dietary Salt Intake, Sugar-Sweetened Beverage Consumption, and Obesity Risk

OBJECTIVE: To determine the association among dietary salt, fluid, and sugar-sweetened beverage (SSB) consumption and weight status in a nationally representative sample of Australian children aged 2 to 16 years. METHODS: Cross-sectional data from the 2007 Australian National Children’s Nutrition and Physical Activity Survey. Consumption of dietary salt, fluid, and SSB was determined via two 24-hour dietary recalls. BMI was calculated from recorded height and weight. Regression analysis was used to assess the association between salt, fluid, SSB consumption, and weight status. RESULTS: Of the 4283 participants, 62% reported consuming SSBs. Older children and those of lower socioeconomic status (SES) were more likely to consume SSBs (both Ps < .001). Dietary salt intake was positively associated with fluid consumption (r = 0.42, P < .001); each additional 1 g/d of salt was associated with a 46 g/d greater intake of fluid, adjusted for age, gender, BMI, and SES (P < .001). In those consuming SSBs (n = 2571), salt intake was positively associated with SSB consumption (r = 0.35, P < .001); each additional 1 g/d of salt was associated with a 17 g/d greater intake of SSB, adjusted for age, gender, SES, and energy (P < .001). Participants who consumed more than 1 serving (≥250 g) of SSB were 26% more likely to be overweight/obese (odds ratio: 1.26, 95% confidence interval: 1.03–1.53). CONCLUSIONS: Dietary salt intake predicted total fluid consumption and SSB consumption within consumers of SSBs. Furthermore, SSB consumption was associated with obesity risk. In addition to the known benefits of lowering blood pressure, salt reduction strategies may be useful in childhood obesity prevention efforts.

Self-reported ballet classes undertaken at age 10-12 years and hip bone mineral density in later life

The major effect of weightbearing exercise on adult bone mass may be exerted during childhood. We examined the relationship between reported hours of ballet classes per week undertaken as a child and adult bone mineral density (BMD) at the hip, spine, and forearm. We performed a retrospective cohort study in 99 female retired dancers (mean age 51 years, SD 14 years) and 99 normal controls, derived from a twin study, matched hierarchically for age, height, weight and menopausal status. Starting age of ballet was recalled and weekly hours of ballet as a child was self-reported on two occasions. BMD was measured using dual-energy X-ray absorptiometry and reported as a Z-score. Self-reported hours of ballet class undertaken per week at each age between 10 and 12 years was positively associated with a difference in BMD between dancers and controls at both the femoral neck site (β=0.73,p=0.001) and the total hip site (β=0.55,p <0.01). These associations were unaffected by adjustment for covariates including measures of adult activity (current physical activity, years of fulltime ballet), measures of menstrual disturbance (age of menarche, history of irregular menses), dietary history (calcium intake as a child, adolescent or adult) or lifestyle factors (lifetime smoking, lifetime alcohol). Although starting age of ballet was negatively associated with weight-adjusted within-pair hip BMD difference, it was no longer associated after adjustment for weekly hours of ballet. There was no relationship between hours of ballet undertaken as a child and differences in BMD at the lumbar spine or upper limb, at any age. Our data suggest that classical ballet classes undertaken between the ages of 10 and 12 years are independently and positively associated with a difference in hip BMD between dancers and controls. The findings are consistent with the hypothesis that this age range identifies a stage of development when the proximal femur is particularly responsive to weightbearing exercise.