Vitamin D deficiency in Tasmania: a whole of life perspective

Prior Nonmelanoma Skin Cancer is Associated with Fewer Fractures, More Vitamin D Sufficiency, Greater Bone Mineral Density, and Improved Bone Microarchitecture in Older Adults

BACKGROUND

Prior nonmelanoma skin cancer (NMSC), a biomarker of cumulative lifetime sun exposure, is associated with reduced fracture risk later in life. The mechanism is unknown.

METHODS

Prospective cohort analysis of 1099 community-dwelling adults aged 50-80 years with baseline and 10-year follow-up assessments. Histopathologically-confirmed NMSC diagnosis was established by linkage with the Tasmanian Cancer Registry. Bone mineral density (BMD) and vertebral deformity were quantified by DXA, 25-hydroxyvitamin D (25(OH)D) by radioimmunoassay, bone microarchitecture by high-resolution peripheral quantitative CT, melanin density by spectrophotometry, and skin photosensitivity and clinical fracture by questionnaire. 25(OH)D <50 nmol/L was considered deficient.

RESULTS

Participants with an NMSC reported prior to baseline were less likely to sustain an incident vertebral deformity over 10 years (RR = 0.74, P = .036). There were similar reductions for other fracture types but these did not reach significance. Prior NMSC was associated with baseline (RR = 1.23, P = .005) and 10-year longitudinal (RR = 5.9, P = .014) vitamin D sufficiency and greater total body BMD (β = 0.021g/cm2, P = .034), but not falls risk or muscle strength. The relationship between prior NMSC and bone microarchitecture was age-dependent (pinteraction < 0.05). In the oldest age tertile, prior NMSC was associated with greater volumetric BMD (β = 57.8-62.6, P = .002-0.01) and less porosity (β = -4.6 to -5.2, P = .002-0.009) at cortical, compact cortical and outer transitional zones.

CONCLUSIONS

Prior NMSC was associated with fewer incident fractures in community-dwelling older adults. This protective association is most likely mediated by modifiable fracture risk factors associated with an outdoor lifestyle, including 25(OH)D, BMD, and bone microarchitecture.

Population Vitamin D Stores Are Increasing in Tasmania, and This Is Associated With Less BMD Loss Over 10 Years

CONTEXT

Vitamin D deficiency is a common, modifiable determinant of musculoskeletal health.

OBJECTIVE

There are limited data that examine the longitudinal change in population 25-hydroxyvitamin D (25[OH]D) and none that evaluate the long-term skeletal outcomes of longitudinal vitamin D status.

METHODS

A prospective cohort analysis was conducted of community-dwelling adults aged 50 to 80 years who had 25(OH)D assessed by radioimmunoassay and bone mineral density (BMD) by dual-energy x-ray absorptiometry at baseline (n = 1096), 2.5 (n = 870), and 10 (n = 565) years. Sun exposure was quantified by questionnaire and supplement use at clinic review. 25(OH)D less than 50 nmol/L was considered deficient. Participants were provided with their 25(OH)D results.

RESULTS

Over 10 years 25(OH)D increased (52.2 ± 17.0 to 63.5 ± 23.6 nmol/L, P < .001). Participants with baseline deficiency had larger 25(OH)D increases than baseline sufficient participants (19.2 ± 25.3 vs 1.6 ± 23.3 nmol/L, P < .001). Longitudinal change in 25(OH)D was associated with baseline summer (β = 1.46, P < .001) and winter (β = 1.29, P = .003) sun exposure, change in summer (β = 1.27, P = .002) and winter (β = 1.47, P < .001) sun exposure, and vitamin D supplement use (β = 25.0-33.0, P < .001). Persistent vitamin D sufficiency was associated with less BMD loss at the femoral neck (β = 0.020, P = .027), lumbar spine (β = 0.033, P = .003), and total hip (β = 0.023, P = .021) compared to persistent vitamin D deficiency. Achieving vitamin D sufficiency was associated with less BMD loss at the lumbar spine (β = 0.045, P < .001) compared to persistent vitamin D deficiency.

CONCLUSIONS

Population 25(OH)D concentration increased because of a combination of increased sun exposure and supplement use. Maintaining or achieving vitamin D sufficiency was associated with less BMD loss over 10 years.

Prospective associations of osteosarcopenia and osteodynapenia with incident fracture and mortality over 10 years in community-dwelling older adults

AIM

To determine whether older adults with low muscle mass (sarcopenia) and strength (dynapenia), in the presence of osteoporosis/osteopenia, have an increased risk of fracture and mortality over 10 years, compared to those with low muscle or low bone mass alone or with neither condition.

METHODS

1032 participants (52% women; mean age 62.9 ± 7.4 years) were prospectively followed for 10 years. Mortality was ascertained from the death registry and fractures were self-reported. Baseline appendicular lean mass (ALM) was assessed using dual-energy X-ray absorptiometry and normalised to body mass index (BMI). Hand grip strength (HGS) was assessed by dynamometer. Osteosarcopenia and osteodynapenia were defined as having T-scores of the total hip and/or lumbar spine bone mineral density (BMD) < -1 combined with being in the lowest 20% of the sex-specific distribution for ALM/BMI or HGS respectively.

RESULTS

Incident fracture risk was significantly higher in participants who were osteodynapenic (RR = 2.07, 95% CI: 1.26-3.39), dynapenic alone (RR = 1.74, 95% CI: 1.05-2.87), and osteopenic alone (RR = 1.63, 95% CI: 1.15-2.31), compared to those without dynapenia or osteopenia. Mortality risk was significantly higher only in participants with osteosarcopenia (RR = 1.49, 95% CI: 1.01-2.21) compared to those without sarcopenia or osteopenia. However, osteosarcopenia and osteodynapenia did not lead to a significantly greater fracture or mortality risk compared to having these conditions on their own.

CONCLUSION

These findings suggest that the combined effect of osteopenia and sarcopenia or dynapenia on fracture and mortality risk, respectively, may not be greater than that of each individual condition.

Vitamin D levels in childhood and adolescence and cardiovascular risk factors in a cohort of healthy Australian children

As the prevalence of obesity appears to be increasing in Australia's youth the overall objective of this study was to examine serum 25-hydroxyvitamin D (25OHD) concentrations in a cohort of 8-year-olds (n=249) followed up at age 15 (n=162) and explore associations between 25OHD with cardiovascular disease (CVD) risk factors in these populations. This was done in two stages: the first, two cross-sectional analyses (at ages 8 and 15); and the second, a prospective analysis from age 8 to 15. At both ages data on 25OHD, blood lipids, and anthropometry were measured. Date of blood draw was used as a surrogate of sunlight exposure. Results were then analysed by multivariate linear analyses taking into account interaction and confounding. Mean 25OHD concentrations decreased from 94±25nmol/L to 63±16nmol/L between age 8 and 15 years (p<0.001). On cross-sectional analysis of 8year olds, no CVD risk factor was found to be significantly associated with 25OHD concentrations. On cross-sectional analysis of 15year olds lower 25OHD levels were significantly associated with higher body fat (adjusted β=-0.24, p=0.003). Prospectively, lower 25OHD levels in 8-year-old boys, but not girls, were significantly associated with higher blood total cholesterol (adjusted β=-0.28, p=0.040) and triglyceride levels (adjusted β=-0.33, p=0.030) at age 15. The limitation of these data is the relatively small sample sizes, however these results suggest that low 25OHD in childhood needs to be further investigated in larger cohort studies as there may be later cardiovascular consequences in adolescence.

Longitudinal associations between serum 25-hydroxyvitamin D, physical activity, knee pain and dysfunction and physiological falls risk in community-dwelling older adults

AIMS

To describe the longitudinal associations between physiological falls risk, and between-person and within-person effects of 25-hydroxyvitamin D (25OHD), physical activity (PA), knee pain and dysfunction in community-dwelling older people.

METHODS

Data for 1053 participants (51% women; mean age 63 ± 7.4 years) studied at baseline, 2.5, 5, and 10 years were analysed. Falls risk (Z-score) was measured using the Physiological Profile Assessment. Knee pain and dysfunction were assessed using the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC). Moderate-to-vigorous PA (MVPA) was measured using accelerometer. Linear mixed-effect regression models, with adjustment for confounders, were used to estimate the association between physiological falls risk and between-person and within-person effects of PA, 25OHD and WOMAC score.

RESULTS

Between-person effects showed that 10-year average physiological falls risk was lower in participants who had a higher 10-year average 25OHD (β = -0.005 per nmol/l, 95% CI: -0.008, -0.002), log-MVPA (β = -0.16 per minute, 95% CI: -0.22, -0.10) and lower mean WOMAC score (β = 0.005 per-unit score, 95% CI: 0.003, 0.01). Within-person effects showed that a higher physiological falls risk at any time-point was associated with higher than average WOMAC score (β = 0.002 per-unit score, 95% CI: 0.0003, 0.004) and lower than average log-MVPA (β = -0.15 per minute, 95% CI: -0.24, -0.06), but not 25OHD, at the same time-point.

CONCLUSION

Having higher WOMAC global score above an individual's average increases the risk of falling, whereas, increasing one's own MVPA level further reduces their risk of falling. The presence of between-person but not within-person associations for 25OHD suggests the former may be confounded by other factors.

Patients presenting with fractures are likely to be vitamin D deficient: are we getting enough sun?

BACKGROUND

25-Hydroxyvitamin D serves a crucial role in bone metabolism through its role on osteoclast and osteoblastic function. To assess the implication of vitamin D and its relationship to bone fracture and fracture force, we have examined vitamin D levels in patients requiring inpatient fracture management.

METHODS

We performed serological testing of vitamin D levels, calcium, parathyroid hormone and liver function tests on patients admitted to our rural institution in southeastern Australia for inpatient fracture management. All participants completed a questionnaire designed to screen for potential contributing factors to bony fragility. Demographic data were also obtained including age, gender and body mass index. Fracture location and the type of inpatient management as well as the force of injury were included in our analysis.

RESULTS

We recruited 100 patients to the study, with a median age of 72 (range 22-98) of whom 66 were women. Most had low-energy fractures (79%), treated by internal fixation (73%) or arthroplasty (9%) with 18 treated non-operatively. The majority of the patients were at best vitamin D insufficient, <75 nmol/L (77%), and 38% were vitamin D deficient (<50 nmol/L). Only 14 patients had a formal diagnosis of osteoporosis at presentation, with 63 patients claiming daily sun exposure in line with recommendations for vitamin D sufficiency.

CONCLUSIONS

Our data suggest that the prevalence of vitamin D insufficiency and deficiency is common in patients presenting with fractures in southeastern Australia and is not confined to elderly patients. All patients with fractures should be assessed for vitamin D levels and treated in accordance with vitamin D deficiency guidelines.

Contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis

The contribution of vitamin D insufficiency to the pathogenesis of multiple sclerosis (MS) is reviewed. Among the multiple recently discovered actions of vitamin D, an immunomodulatory role has been documented in experimental autoimmune encephalomyelitis and in humans. This action in the peripheral immune system is currently the main known mechanism through which vitamin D might influence MS, but other types of actions could be involved within the central nervous system. Furthermore, vitamin D insufficiency is widespread in temperate countries and in patients with MS at the earliest stages of the disease, suggesting that the deleterious effects related to vitamin D insufficiency may be exerted in these patients. In fact, many genetic and environmental risk factors appear to interact and contribute to MS. In genetics, several human leukocyte antigen (HLA) alleles (more particularly HLA-DRB1*1501) could favour the disease whereas some others could be protective. Some of the genes involved in vitamin D metabolism (e.g. CYP27B1) also play a significant role. Furthermore, three environmental risk factors have been identified: past Epstein-Barr virus infection, vitamin D insufficiency and cigarette smoking. Interactions between genetic and environmental risk or protective factors may occur during the mother's pregnancy and could continue during childhood and adolescence and until the disease is triggered in adulthood, therefore possibly modulating the MS risk throughout the first decades of life. Furthermore, some clinical findings already strongly suggest that vitamin D status influences the relapse rate and radiological lesions in patients with MS, although the results of adequately powered randomized clinical trials using vitamin D supplementation have not yet been reported. While awaiting these incontrovertible results, which might be long in coming, patients with MS who are currently in vitamin D insufficiency should be supplemented, at least for their general health status, using moderate doses of the vitamin.