Caregivers of individuals with borderline personality disorder: The relationship between leading caregiver interventions and psychological distress/positive mental well-being.

Burden and psychological distress are higher in informal caregivers (ICs) of people with severe emotional and behavior dysregulation who have been given a diagnosis of borderline personality disorder (BPD) compared with non-caregivers. The current cross-sectional study examines the difference in outcomes of ICs of people with BPD who have received the intervention Family Connections (FC) and who also led interventions for other caregivers (caregiver-leaders) compared with those who have attended FC but not led caregiver interventions (non-leader-FC participants). The sample for this research is from a larger study (Hayes et al., 2023, Borderline Personality Disorder and Emotion Dysregulation, 10, 31). Data for 347 participants who self-reported receiving FC and completed the McLean Screening Instrument for BPD-Carer Version, the Brief COPE, the Multidimensional Scale of Perceived Social Support, the Kessler Psychological Distress scale, the WHO-5 Well-being Index, and the Coronavirus Anxiety Scale were analyzed. The results found that being a caregiver-leader was associated with higher positive mental well-being and lower psychological distress compared with non-leader-FC participants. Being a caregiver-leader was also associated with significantly greater use of the coping strategy of positive reframing and lower use of behavioral disengagement and self-blame than non-leader-FC participants. The study provides preliminary evidence that for those who have received FC, becoming an intervention leader is associated with better outcomes than caregivers who do not become leaders and provides support for caregiver-led rollout of FC across services.

Self-reported outcomes and patterns of service engagement after an acquired brain injury: a long-term follow-up study.

PRIMARY OBJECTIVE: To describe the clinical characteristics, self-reported outcomes in domains relating to activities of daily living and patterns of service engagement in the survivors of a moderate-to-severe acquired brain injury over seven years. RESEARCH DESIGN: A longitudinal research design was used. METHODS AND PROCEDURES: Thirty-two individuals who sustained a moderate-to-severe acquired brain injury completed a Sociodemographic and Support Questionnaire at one (t1) and seven years (t2) after completing a publicly funded inpatient neurorehabilitation program. MAIN OUTCOMES AND RESULTS: There were minimal changes in independent living, mobility, ability to maintain key relationships and in return to work in the interval between t1 and t2. Sixty-nine percent of participants engaged with two or more allied health professional services and 75% engaged with support services in the community over the seven years. CONCLUSIONS: There were minimal additional gains in outcomes relating to activities of daily-living and there was a high level of service need in the first decade postinjury. Young and middle-aged individuals who sustain an ABI may continue to live in the community for decades with some level of disability and may require ongoing access to services.

Evaluating the national multisite implementation of dialectical behaviour therapy in a community setting: a mixed methods approach.

BACKGROUND: The implementation of evidence-based interventions for borderline personality disorder in community settings is important given that individuals with this diagnosis are often extensive users of both inpatient and outpatient mental health services. Although work in this area is limited, previous studies have identified facilitators and barriers to successful DBT implementation. This study seeks to expand on previous work by evaluating a coordinated implementation of DBT in community settings at a national level. The Consolidated Framework for Implementation Research (CFIR) (Damschroder et al., Implementation Sci. 4:50, 2009) provided structural guidance for this national level coordinated implementation. METHODS: A mixed methods approach was utilised to explore the national multisite implementation of DBT from the perspective of team leaders and therapists who participated in the coordinated training and subsequent implementation of DBT. Qualitative interviews with DBT team leaders (n = 8) explored their experiences of implementing DBT in their local service and was analysed using content analysis. Quantitative surveys from DBT therapists (n = 74) examined their experience of multiple aspects of the implementation process including orienting the system, and preparations and support for implementation. Frequencies of responses were calculated. Written qualitative feedback was analysed using content analysis. RESULTS: Five themes were identified from the interview data: team formation, implementation preparation, client selection, service level challenges and team leader role. Participants identified team size and support for the team leader as key points for consideration in DBT implementation. Key challenges encountered were the lack of system support to facilitate phone coaching and a lack of allocated time to focus on DBT. Implementation facilitators included having dedicated team members and support from management. CONCLUSIONS: The barriers and facilitators identified in this study are broadly similar to those reported in previous research. Barriers and facilitators were identified across several domains of the CFIR and are consistent with a recently published DBT implementation Framework (Toms et al., Borderline Personal Disord Emot Dysregul. 6: 2, 2019). Future research should pay particular attention to the domain of characteristics of individuals involved in DBT implementation. The results highlight the importance of a mandated service plan for the coordinated implementation of an evidence-based treatment in a public health service. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03180541; Registered June 7th 2017 'retrospectively registered'.

Phylloquinone Intakes and Food Sources and Vitamin K Status in a Nationally Representative Sample of Irish Adults.

BACKGROUND: Data from a nationally representative sample of 18- to 64-y-old Irish adults conducted in 1999 highlighted low phylloquinone intakes. That survey, however, did not include older adults (aged ≥65 y), a subgroup that is potentially at higher risk of low phylloquinone intakes, or a biomarker of vitamin K status. OBJECTIVES: The objectives of this work were to measure the phylloquinone intake and its adequacy and the serum percentage of undercarboxylated osteocalcin (%ucOC), a vitamin K status biomarker, in a nationally representative sample of Irish adults aged 18-90 y, and to compare these newer data on dietary phylloquinone in adults aged 18-64 y with those from the previous survey. METHODS: Data and biobanked serum samples from the National Adult Nutrition Survey, a randomly selected sample of Irish adults aged 18-90 y (N = 1500), were accessed. Phylloquinone intakes were estimated from 4-d food diary data and were compared across age groups (18-35, 36-50, 51-64, and ≥65 y). Serum %ucOC was assessed by immunoassay (n = 692). RESULTS: The mean ± SD intake of phylloquinone from all sources was 85.2 ± 59.1 µg/d, 99% of which was derived from food. Phylloquinone intakes and serum %ucOC were significantly (P < 0.05) lower (14-25%) and higher (27-39%), respectively, in the 18- to 35-y age group than in the 36- to 50-y, 51- to 64-y, and ≥65-y age groups (no differences between these 3 groups; P > 0.2 in all cases). Mean phylloquinone intakes had increased (P < 0.01) modestly (6 µg/d) in 18-64-y-olds across a decade. Of the total study population, 55% had phylloquinone intakes below the United Kingdom recommended intake of 1 µg ⋅ kg body weight-1 ⋅ d-1 CONCLUSION: Our study shows that younger adults (aged 18-35 y) appear to be at higher risk of inadequate vitamin K intake and lower vitamin K status, the health implications of which are unclear and warrant further investigation.

Significance of serum 24,25-dihydroxyvitamin D in the assessment of vitamin D status: a double-edged sword?

BACKGROUND: 24,25-Dihydroxyvitamin D [24,25(OH)2D] in serum may be both a nuisance and nutritionally valuable. METHODS: We investigated the impact of 24,25(OH)2D3 on the performance of commercially available immunoassays for serum total 25-hydroxyvitamin D [25(OH)D] using (a) serum from a nationally representative sample of adults, (b) serum from a spiking experiment, and (c) data from the UK Vitamin D External Quality Assurance Scheme (DEQAS). We also investigated the utility of the serum ratio of 24,25(OH)2D3 to 25(OH)D as an index of inactivation and of response to vitamin D supplementation using randomized controlled trial (RCT) data. Measurement of 24,25(OH)2D in sera by a LC-MS/MS method allowed for an investigation of its impact on immunoassay-derived serum 25(OH)D values as well as its clinical utility. We report data from a nationally representative sample of adults, a recent vitamin D RCT in older adults, and DEQAS. RESULTS: 24,25(OH)2D3 contributed to the positive bias observed in some immunoassays relative to LC-MS/MS-derived estimates for total 25(OH)D. A spiking experiment showed that the degree of cross-reactivity with 24,25(OH)2D was high and may underpin this positive bias. Adjustment for 24,25(OH)2D3 concentration brought estimates closer to true values. Data from the vitamin D RCT showed that the ratio of 24,25(OH)2D3 to 25(OH)D was associated with serum 25(OH)D3 and with response of serum 25(OH)D to vitamin D supplementation. CONCLUSIONS: Our findings highlight that the effect of 24,25(OH)2D3 in serum is a double-edged sword-an interferent for some immunoassays, yet potentially informative of nutritional status.

The 3 epimer of 25-hydroxycholecalciferol is present in the circulation of the majority of adults in a nationally representative sample and has endogenous origins.

Fundamental knowledge gaps in relation to the 3 epimer of 25-hydroxycholecalciferol [3-epi-25(OH)D3] limit our understanding of its relevance for vitamin D nutrition and health. The aims of this study were to characterize the 3-epi-25(OH)D3 concentrations in a nationally representative sample of adults and explore its determinants. We also used data from a recent randomized controlled trial (RCT) of supplemental cholecalciferol (vitamin D3) conducted in winter in older adults to directly test the impact of changes in vitamin D status on serum 3-epi-25(OH)D3 concentrations. Serum 25-hydroxycholecalciferol [25(OH)D3] and 3-epi-25(OH)D3 concentrations (via LC-tandem mass spectrometry) from our vitamin D3 RCT in adults (aged ≥50 y) and data on dietary, lifestyle, and biochemical characteristics of participants of the recent National Adult Nutrition Survey in Ireland (aged 18-84 y; n = 1122) were used in the present work. In the subsample of participants who had serum 3-epi-25(OH)D3 concentrations greater than the limit of quantification (n = 1082; 96.4%), the mean, 10th, 50th (median), and 90th percentile concentrations were 2.50, 1.05, 2.18, and 4.30 nmol/L, respectively, whereas the maximum 3-epi-25(OH)D3 concentration was 15.0 nmol/L. A regression model [explaining 29.9% of the variability in serum 3-epi-25(OH)D3] showed that age >50 y, vitamin D supplement use, dietary vitamin D, meat intake, season of blood sampling, and sun exposure habits were significant positive determinants, whereas increasing waist circumference and serum 25-hydroxyergocalciferol concentration were significant negative determinants. The RCT data showed that mean serum 25(OH)D3 and 3-epi-25(OH)D3 concentrations increased (49.3% and 42.1%, respectively) and decreased (-28.0% and -29.1%, respectively) significantly (P < 0.0001) with vitamin D3 (20 µg/d) and placebo supplementation, respectively, over 15 wk of winter. In conclusion, we provide data on serum 3-epi-25(OH)D3 in a nationally representative sample of adults. Our combined observational and RCT data might suggest that both dietary supply and dermal synthesis of vitamin D3 contribute to serum 3-epi-25(OH)D3 concentration.

The relationship between social support, coping strategies and psychological distress and positive mental well-being in carers of people with borderline personality disorder.

BACKGROUND: Informal carers of people with BPD experience high levels of burden and psychological distress relative to other populations. There is a scarcity of research evidencing the influence of modifiable factors on carer outcomes to inform interventions. This study aimed to investigate the relationship between social support, coping strategies and psychological distress and positive mental well-being in this carer population. METHODS: In this cross-sectional study, 1207 carers completed the McLean Screening Instrument for BPD-Carer Version, the Brief COPE, the Multidimensional Scale of Perceived Social Support, the Kessler Psychological Distress scale, the WHO-5 Well-being Index, and the Coronavirus Anxiety Scale. Data for 863 participants who met the inclusion criteria were analysed. RESULTS: Carers reported low positive mental well-being and high psychological distress. Perceived social support and several coping strategies were significant unique predictors of psychological distress and positive mental well-being. Perceived social support and positive reframing were the strongest predictors of higher positive mental well-being and lower psychological distress. Self-blame, behavioural disengagement and substance use were the strongest predictors of adverse outcomes. CONCLUSIONS: The findings evidence modifiable factors that may be used to improve informal carer outcomes and indicate that carer interventions may be improved by focusing on reducing the use of self-blame, behavioural disengagement and substance use, and development of quality social support and skills to positively reframe caregiving situations.

Dialectical behaviour therapy skills reconsidered: applying skills training to emotionally dysregulated individuals who do not engage in suicidal and self-harming behaviours.

BACKGROUND: Dialectical behaviour therapy (DBT) is an evidence-based intervention for borderline personality disorder (BPD) but is an intensive treatment with significant health service costs. Access to DBT can sometimes be restricted due to limited resources. Positive results have been reported for the use of DBT skills training (DBT-ST), one of the four modes of standard DBT, in the treatment of individuals with BPD who self-harm. This study evaluates DBT-ST for a subgroup of individuals attending community mental health services who may have a diagnosis of BPD (or emerging BPD traits) but who are not actively self-harming. METHODS: Participants in this study were 100 adults attending community mental health services with a diagnosis of BPD, emerging BPD traits or emotion dysregulation who were not actively self-harming. The majority of participants were female (71%), aged 25-34 years (32%), single (48%) and unemployed (34%). Participants partook in a 24-week DBT-ST intervention delivered by DBT therapists. Outcome measures included the Difficulties in Emotion Regulation Scale (DERS), the DBT Ways of Coping Checklist (DBT-WCCL) and the Five Facet Mindfulness Questionnaire (FFMQ). Measures were administered at pre-intervention, at the end of each skills module, and at post-intervention. RESULTS: Significant reductions in emotion dysregulation (DERS) and dysfunctional coping (DBT-WCCL) scores were reported from pre- to post-intervention (p < .001). A significant increase in mindfulness scores (FFMQ) and DBT skill use (DBT-WCCL) was also observed (p < .001). However, the drop-out rate was high (49% at post-intervention). DISCUSSION: The results of this uncontrolled study suggest that a standalone 24-week DBT-ST intervention may have a beneficial impact in terms of a reduction in emotion dysregulation and dysfunctional coping, and an increase in mindfulness and DBT skills use in patients with BPD/ emerging BPD traits who are not currently engaging in self-harm. Adequately powered randomised controlled trials are required to determine treatment efficacy in comparison to standard DBT for this population.

Does an adapted Dialectical Behaviour Therapy skills training programme result in positive outcomes for participants with a dual diagnosis? A mixed methods study.

BACKGROUND: Treating severe emotional dysregulation and co-occurring substance misuse is challenging. Dialectical behaviour therapy (DBT) is a comprehensive and evidence-based treatment for borderline personality disorder (BPD). It has been hypothesised that the skills training, which is a facet of the full DBT programme, might be effective for people with severe emotional dysregulation and other co-occurring conditions, but who do not meet the criteria for BPD. However, there is limited research on standalone DBT skills training for people with substance misuse and emotional dysregulation. METHODS: A mixed methods study employing an explanatory sequential design was conducted where participants with a dual diagnosis (n = 64) were recruited from a community-based public addiction treatment service in Ireland between March 2015 and January 2018. DBT therapists screened potential participants against the study eligibility criteria. Quantitative self-report measures examining emotion regulation, mindfulness, adaptive and maladaptive coping responses including substance misuse, and qualitative feedback from participants were collected. Quantitative data were summarised by their mean and standard deviation and multilevel linear mixed effects models were used to estimate the mean change from baseline to post-intervention and the 6-month follow-up period. Thematic analysis was used to analyse the qualitative data. RESULTS: Quantitative results indicated reductions in binge drinking and use of Class A, B and C drug use from pre-intervention (T1) to the 6-month follow-up (T3). Additionally, significant improvements were noted for mindfulness practice and DBT skills use from T1 to T3 (p < 0.001). There were also significant reductions in dysfunctional coping and emotional dysregulation from T1 to T3 (p < 0.001). Significant differences were identified from pre to post intervention in reported substance use, p = 0.002. However, there were no significant differences between pre-intervention and 6-month follow up reports of substance use or at post-intervention to 6 month follow up. Qualitative findings indicated three superordinate themes in relation to participants' experiences of a DBT skills training programme, adapted from standard DBT: (1) new lease of life; (2) need for continued formal aftercare and (3) programme improvements. Participants described reductions in substance misuse, while having increased confidence to use the DBT skills they had learned in the programme to deal with difficult emotions and life stressors. CONCLUSIONS: This DBT skills training programme, adapted from standard DBT, showed positive results for participants and appears effective in treating people with co-occurring disorders. Qualitative results of this mixed methods study corroborate the quantitative results indicating that the experiences of participants have been positive. The study indicates that a DBT skills programme may provide a useful therapeutic approach to managing co-occurring symptoms.

Reconciling age-related changes in behavioural and neural indices of human perceptual decision-making.

Ageing impacts on decision-making behaviour across a range of cognitive tasks and scenarios. Computational modelling has proved valuable in providing mechanistic interpretations of these age-related differences; however, the extent to which model parameter differences accurately reflect changes to the underlying neural computations remains unclear. Here, we report that age-related effects on neural signatures of decision formation are inconsistent with behavioural fits derived from a prominent accumulation-to-bound model. Most notably, model-predicted bound differences were absent neurophysiologically. However, constraining the model to match the decision-predictive elements of the brain signals provided more parsimonious fits to behaviour and generated predictions regarding the neural data that were empirically validated. These included a task-dependent slowing of evidence accumulation among older adults and reduced between-trial accumulation rate variability, which was linked to enhanced attentional engagement. Our findings highlight how combining neurophysiological measurements with computational modelling can yield unique insights into group differences in neural decision mechanisms.

Vitamin D-biofortified beef: A comparison of cholecalciferol with synthetic versus UVB-mushroom-derived ergosterol as feed source.

This study investigates dietary fortification of heifer feeds with cholecalciferol and ergocalciferol sources and effects on beef total vitamin D activity, vitamer, respective 25-hydroxymetabolite contents, and meat quality. Thirty heifers were allocated to one of three dietary treatments [(1) basal diet + 4000 IU of vitamin D3 (Vit D3); (2) basal diet + 4000 IU of vitamin D2 (Vit D2); and (3) basal diet + 4000 IU of vitamin D2-enriched mushrooms (Mushroom D2)] for a 30 day pre-slaughter period. Supplementation of heifer diets with Vit D3 yielded higher (p < 0.001) Longissimus thoracis (LT) total vitamin D activity (by 38-56%; p < 0.05) and serum 25-OH-D concentration (by 20-36%; p < 0.05), compared to that from Vit D2 and Mushroom D2 supplemented animals. Irrespective of vitamin D source, carcass characteristics, sensory and meat quality parameter were unaffected (p > 0.05) by the dietary treatments. In conclusion, vitamin D3 biofortification of cattle diets is the most efficacious way to enhance total beef vitamin D activity.

The use of synthetic and natural vitamin D sources in pig diets to improve meat quality and vitamin D content.

This study investigated the effects of synthetic and natural sources of vitamin D biofortification in pig diets on pork vitamin D activity and pork quality. One hundred and twenty pigs (60 male, 60 female) were assigned to one of four dietary treatments for a 55 d feeding period. The dietary treatments were (1)50 µg vitamin D3/kg of feed; (2)50 µg of 25-hydroxvitamin D3/kg of feed (25-OH-D3); (3)50 µg vitamin D2/kg of feed; (4)50 µg vitamin D2-enriched mushrooms/kg of feed (Mushroom D2). The pigs offered the 25-OH-D3 diet exhibited the highest (P < 0.001) serum total 25-hydroxyvitamin D concentration and subsequently exhibited the highest (P < 0.05) Longissimus thoracis (LT) total vitamin D activity. Mushroom D2 and 25-OH-D3 supplementation increased pork antioxidant status. The vitamin D2-enriched mushrooms improved (P < 0.05) pig performance, carcass weight and LT colour. In conclusion, 25-OH-D3 is the most successful source for increasing pork vitamin D activity, while Mushroom D2 may be a new avenue to improve animal performance and pork quality.

Food-based solutions for vitamin D deficiency: putting policy into practice and the key role for research.

Recent re-evaluations of dietary reference values (DRV) for vitamin D have established intake requirements between 10 and 20 µg/d. National nutrition surveys indicate that habitual mean intakes of vitamin D in the population are typically in the range 3-7 µg/d. As vitamin D supplementation will not be effective at a population level because the uptake is generally low, creative food-based solutions are needed to bridge the gap between current intakes and these new requirement values. The overarching aim of this review is to highlight how food-based solutions can have an important role in bridging this gap and counteracting vitamin D inadequacy in Europe and elsewhere. The present review initially briefly overviews very recent new European DRV for vitamin D and, while not in agreement on requirement estimates, how they point very clearly to the need for food-based solutions. The review discusses the need for traditional fortification of foods in the dairy and other sectors, and finally overviews recent advances in the area of biofortification of food with vitamin D. In conclusion, increasing vitamin D intakes across the population distribution is important from a public health perspective to reduce the high degree of inadequacy of vitamin D intake in Europe. Fortification, including biofortification, of a wider range of foods, which accommodate diversity, is likely to have the potential to increase vitamin D intakes across the population distribution. Research has had, and will continue to have, a key role in terms of developing food-based solutions and tackling vitamin D deficiency.

Red meat's role in addressing 'nutrients of public health concern'.

The role of red meat, particularly lean cuts, in healthy eating guidelines has been highlighted in most developed nations. Despite this, the public have received some mixed messages in relation to meat. Nutrition claims in Europe and nutrient content claims in the US may have important roles in providing consumer confidence and a better appreciation of the importance of red meat to achieving nutrient adequacy. In particular, it is noteworthy that nutrition/nutrient content claims for red meat could be made for four out of the seven nutrients of public health concern as designated in the 2015-2020 Dietary Guidelines for Americans, namely sodium, potassium, iron, vitamin D, the intakes of which have also been shown to be problematic for European populations. While beef may already qualify to carry a 'Source of vitamin D' claim, other red meats do not. Vitamin D biofortification approaches may have the ability to enhance the vitamin D and/or 25-hydroxyvitamin content of red meat, facilitating additional nutrition/nutrient content claims.

Cholecalciferol supplementation of heifer diets increases beef vitamin D concentration and improves beef tenderness.

This study investigated the effects of cholecalciferol (vitamin D3) supplementation on beef vitamin D activity, beef tenderness and sensory attributes. Thirty heifers were randomly allocated to one of three finishing dietary treatments [(T1) basal diet+0IU vitamin D3; (T2) basal diet+2000IU vitamin D3; and (T3) basal diet+4000IU vitamin D3] for a 30day period pre-slaughter. Vitamin D3 supplementation linearly increased serum 25-hydroxyvitamin D3 (25-OH-D3) concentrations (R2=0.48), Longissimus thoracis (LT) total vitamin D activity (R2=0.78) as well as individually vitamin D3 (R2=0.84) and 25-OH-D3 (R2=0.75). The highest vitamin D3 inclusion diet (T3) had a 42% increase (P<0.001) in LT vitamin D activity compared to the intermediate diet (T2) and a 145% increase over the lowest level diet (T1). Vitamin D3 supplementation decreased LT shear (P<0.05) force values after 14days chilling. Sensory parameters were not affected (P>0.05). In conclusion, through short-term vitamin D3 supplementation of cattle diets, beef vitamin D activity can successfully be enhanced.

Vitamin D-enhanced eggs are protective of wintertime serum 25-hydroxyvitamin D in a randomized controlled trial of adults.

BACKGROUND: Despite numerous animal studies that have illustrated the impact of additional vitamin D in the diet of hens on the resulting egg vitamin D content, the effect of the consumption of such eggs on vitamin D status of healthy individuals has not, to our knowledge, been tested. OBJECTIVE: We performed a randomized controlled trial (RCT) to investigate the effect of the consumption of vitamin D-enhanced eggs (produced by feeding hens at the maximum concentration of vitamin D3 or serum 25-hydroxyvitamin D [25(OH)D3] lawfully allowed in feed) on winter serum 25(OH)D in healthy adults. DESIGN: We conducted an 8-wk winter RCT in adults aged 45-70 y (n = 55) who were stratified into 3 groups and were requested to consume ≤2 eggs/wk (control group, in which status was expected to decline), 7 vitamin D3-enhanced eggs/wk, or seven 25(OH)D3-enhanced eggs/wk. Serum 25(OH)D was the primary outcome. RESULTS: Although there was no significant difference (P > 0.1; ANOVA) in the mean preintervention serum 25(OH)D in the 3 groups, it was ∼7-8 nmol/L lower in the control group than in the 2 groups who consumed vitamin D-enhanced eggs. With the use of an ANCOVA, in which baseline 25(OH)D was accounted for, vitamin D3-egg and 25(OH)D3-egg groups were shown to have had significantly higher (P ≤ 0.005) postintervention serum 25(OH)D than in the control group. With the use of a within-group analysis, it was shown that, although serum 25(OH)D in the control group significantly decreased over winter (mean ± SD: -6.4 ± 6.7 nmol/L; P = 0.001), there was no change in the 2 groups who consumed vitamin D-enhanced eggs (P > 0.1 for both). CONCLUSION: Weekly consumption of 7 vitamin D-enhanced eggs has an important impact on winter vitamin D status in adults. This trial was registered at clinicaltrials.gov as NCT02678364.

Dietary calcium does not interact with vitamin D3 in terms of determining the response and catabolism of serum 25-hydroxyvitamin D during winter in older adults.

BACKGROUND: Interactions between calcium and vitamin D may have implications for the regulation of serum 25-hydroxyvitamin D [25(OH)D] and its catabolism and, consequently, the vitamin D dietary requirement. OBJECTIVE: We investigated whether different calcium intakes influenced serum 25(OH)D and indexes of vitamin D activation and catabolism during winter and in the context of both adequate and inadequate vitamin D intakes. DESIGN: A 15-wk winter-based, randomized, placebo-controlled, double-blind vitamin D3 intervention (20 µg/d) study was carried out in free-living men and women aged ≥50 y (n = 125) who were stratified according to calcium intakes [moderate-low (<700 mg/d) or high (>1000 mg/d) intake]. The serum 25(OH)D concentration was the primary outcome, and serum calcium, parathyroid hormone (PTH), 1,25-dihydroxyvitamin D [1,25(OH)2D], 24,25-dihydroxyvitamin D [24,25(OH)2D], the ratio of 24,25(OH)2D to 25(OH)D, vitamin D-binding protein, and free 25(OH)D were exploratory outcomes. RESULTS: A repeated-measures ANOVA showed there was no significant (P = 0.2) time × vitamin D treatment × calcium intake grouping interaction effect on the mean serum 25(OH)D concentration over the 15-wk intervention period. Serum 25(OH)D concentrations increased (P ≤ 0.005) and decreased (P ≤ 0.002) in vitamin D3 and placebo groups, respectively, and were of similar magnitudes in subjects with calcium intakes <700 mg/d (and even <550 mg/d) compared with >1000 mg/d. The response of serum PTH, 1,25(OH)2D, 24,25(OH)2D, the ratio of 24,25(OH)2D to 25(OH)D, and free 25(OH)D significantly differed in vitamin D3 and placebo groups but not by calcium intake grouping. CONCLUSIONS: We found no evidence of a vitamin D sparing effect of high calcium intake, which has been referred to by some authors as "vitamin D economy." Thus, recent dietary vitamin D requirement estimates will cover the vitamin D needs of even those individuals who have inadequate calcium intakes.