Developing a national primary care research network: a qualitative study of stakeholder views.

Introduction Primary care research is critical to address Aotearoa New Zealand's (NZ) health sector challenges. These include health inequities, workforce issues and the need for evaluation of health system changes. Internationally, primary care data are routinely collected and used to understand these issues by primary care research and surveillance networks (PCRN). NZ currently has no such infrastructure. Aim To explore health sector stakeholders' views on the utility of, and critical elements needed for, a national PCRN in NZ. Methods Twenty semi-structured interviews and a focus group were conducted with key stakeholders, representing different perspectives within the health sector, including Hauora Maori providers. Data were analysed thematically. Results Six themes were identified that included both challenges within current primary care research and ideas for a future network. The themes were: disconnection between research, practice and policy; desire for better infrastructure; improving health equity for Maori and other groups who experience inequity; responding to the research needs of communities; reciprocity between research and practice; and the need for data to allow evidence-informed decision-making. Improving health equity for Maori was identified as a critical function for a national PCRN. Discussion Stakeholders identified challenges in conducting primary care research and translating research into practice and policy in NZ. Stakeholders from across the health sector supported a national PCRN and identified what its function should be and how it could operate. These views were used to develop a set of recommendations to guide the development of a national PCRN.

Managing the misuse potential and risk of psychological harm from gabapentinoids in primary care in New Zealand.

Gabapentinoid prescribing is increasing in New Zealand. International evidence suggests that this prescribing trend is followed by increasing harms, including misuse, dependence, overdose, and psychological harms including suicidal thoughts or behaviours. However, there is limited guidance for prescribers on how to manage these potential harms. Here, we summarise the current international literature and identify three main risk factors that can be used for screening purposes when considering prescribing a gabapentinoid, to identify patients that may be at greater risk of harm. Based on current knowledge of harms, we provide guidance to prescribers on monitoring patients taking gabapentinoids. Finally, we summarise the evidence regarding tapering, and highlight key knowledge gaps including other interventions, referral, and data from primary care populations.

Navigating the health system during COVID-19: primary care perspectives on delayed patient care.

AIM: The primary care response to the coronavirus disease 2019 (COVID-19) pandemic has required significant changes to the delivery of healthcare by general practices. This study explores the experiences of New Zealand general practice teams in their perception of delayed patient care during the early stages of the pandemic. METHOD: We qualitatively analysed a subtheme of delayed patient care of the General Practice Pandemic Experience New Zealand study, where general practice team members nationwide were invited to participate in five surveys between May and August 2020. RESULTS: 164 participants initially enrolled in the study, with 78 (48%) completing all surveys. Four delayed-care themes were identified: patient contributors, health system contributors, impacts and opportunities for minimisation. Respondents noted that patients avoided healthcare, downplayed symptoms and feared going out. Non-essential care was put on hold, allied services were reduced and access to secondary care was variable. Certain diseases and screening were commonly impacted. As lockdown lifted a backlog of work resulted. Flexible review periods, outreach care, self-screening, cross-sector collaboration and improved public awareness were strategies for timely healthcare. CONCLUSION: Reducing barriers to patients seeking care and improving integration and relationships across the health system would minimise future pandemic disruption and delayed patient healthcare.

'Here to stay': changes to prescribing medication in general practice during the COVID-19 pandemic in New Zealand.

INTRODUCTION The delivery of health care by primary care general practices rapidly changed in response to the coronavirus disease 2019 (COVID-19) pandemic in early 2020. AIM This study explores the experience of a large group of New Zealand general practice health-care professionals with changes to prescribing medication during the COVID-19 pandemic. METHODS We qualitatively analysed a subtheme on prescribing medication from the General Practice Pandemic Experience New Zealand (GPPENZ) study, where general practice team members nationwide were invited to participate in five surveys over 16 weeks from 8 May 2020. RESULTS Overall, 78 (48%) of 164 participants enrolled in the study completed all surveys. Five themes were identified: changes to prescribing medicines; benefits of electronic prescription; technical challenges; clinical and medication supply challenges; and opportunities for the future. There was a rapid adoption of electronic prescribing as an adjunct to use of telehealth, minimising in-person consultations and paper prescription handling. Many found electronic prescribing an efficient and streamlined processes, whereas others had technical barriers and transmission to pharmacies was unreliable with sometimes incompatible systems. There was initially increased demand for repeat medications, and at the same time, concern that vulnerable patients did not have usual access to medication. The benefits of innovation at a time of crisis were recognised and respondents were optimistic that e-prescribing technical challenges could be resolved. DISCUSSION Improving e-prescribing technology between prescribers and dispensers, initiatives to maintain access to medication, particularly for vulnerable populations, and permanent regulatory changes will help patients continue to access their medications through future pandemic disruption.

Empty waiting rooms: the New Zealand general practice experience with telehealth during the COVID-19 pandemic.

AIM: The primary care response to the coronavirus disease 2019 (COVID-19) pandemic in early 2020 required significant changes to the delivery of healthcare by general practices. This study explores the experiences of New Zealand general practice teams in their use of telehealth during the early stages of the COVID-19 pandemic in New Zealand. METHOD: We qualitatively analysed a subtheme on telehealth of the General Practice Pandemic Experience New Zealand (GPPENZ) study, where general practice team members across the country were invited to participate in five surveys between 8 May 2020 to 27 August 2020. RESULTS: 164 participants enrolled in the study during survey one, with 78 (48%) completing all surveys. Five telehealth themes were identified: benefits, limitations, paying for consults, changes over time and plans for future use. Benefits included rapid triage, convenience and efficiency, and limitations included financial and technical barriers for practices and patients and concerns about clinical risk. Respondents rapidly returned to in-person consultations and wanted clarification of conditions suited to telehealth, better infrastructure and funding. CONCLUSION: To equitably sustain telehealth use, the following are required: adequate funding, training, processes communicated to patients, improved patient access to technology and technological literacy, virtual physical examination methods and integration with existing primary health care services.

Effect of monthly vitamin D supplementation on antibiotic prescribing in older adults: a post hoc analysis of a randomized controlled trial.

BACKGROUND: Observational studies have reported that low vitamin D status is associated with increased risk of antibiotic use. However, trials on the effect of vitamin D supplementation on antibiotics are limited and inconclusive. OBJECTIVES: The main objective of this study was to determine the effect of monthly vitamin D supplementation on the proportion of adults with ≥1 prescriptions of antibiotics. The secondary outcomes were to determine the effect of monthly vitamin D supplementation on the number of antibiotic prescriptions and the number of days on antibiotics. METHODS: This was a post hoc analysis of a randomized, double-blinded, placebo-controlled trial with community-based older adults who were randomly assigned to receive monthly 100,000 IU of vitamin D or identical placebo. All analyses were based on the principle of "intention to treat." RR from log-binomial models and the incidence rate ratio (IRR) from negative binomial models were estimated for primary and secondary outcomes after adjusting for age, sex, and ethnicity. RESULTS: A total of 5108 participants aged 50-84 y were randomly assigned to vitamin D supplementation (n = 2558) or placebo (n = 2550) groups. During a median follow-up of 3.3 y, 4211 (82%) participants were prescribed antibiotics. There was no difference in the proportion of participants prescribed antibiotics between vitamin D (82%) and placebo (83%) groups (adjusted RR: 0.99; 95% CI: 0.97, 1.01; P = 0.42). Similarly, the number of antibiotic prescriptions per person-year did not differ between the 2 treatment groups (adjusted IRR: 0.98; 95% CI: 0.93, 1.04; P = 0.58). However, the number of days on antibiotics per person-year was significantly lower in the vitamin D group (mean ± SEM: 15 ± 0.7) compared with the placebo group (mean ± SEM: 17 ± 0.8) (adjusted IRR: 0.90; 95% CI: 0.82, 0.98; P = 0.01), especially for the tetracyclines (IRR: 0.65; 95% CI: 0.50, 0.85; P = 0.002). CONCLUSIONS: Long-term, monthly, high-dose vitamin D3 supplementation did not prevent antibiotic prescribing in older adults, but the vitamin D group had fewer days per person-year on antibiotics. Further research is required to replicate these findings. This trial was registered at www.anzctr.org.au as ACTRN12611000402943.

Effect of Monthly Vitamin D Supplementation on Preventing Exacerbations of Asthma or Chronic Obstructive Pulmonary Disease in Older Adults: Post Hoc Analysis of a Randomized Controlled Trial.

Randomized controlled trials have suggested that vitamin D supplementation can prevent asthma and chronic obstructive pulmonary disease (COPD) exacerbations. For COPD, the benefit appears to be limited to individuals with baseline 25-hydroxyvitamin D (25OHD) levels <25 nmol/L. We performed a post hoc analysis of data from a randomized, double-blinded, placebo-controlled trial to investigate the effect that monthly, high-dose vitamin D supplementation (versus placebo) had on older adults with asthma and/or COPD. Specifically, we investigated whether vitamin D supplementation prevented exacerbations of these conditions. Participants were randomly assigned either to an initial oral dose of 200,000 IU vitamin D3 followed by 100,000 IU monthly or to placebo, with an average follow-up period of 3.3 years. Among the 5110 participants, 775 had asthma or COPD at the beginning of the study, and were eligible for inclusion in this analysis. Exacerbations were defined by the prescription of a short-burst of oral corticosteroids. The mean age of the participants was 67 years old, and 56% were male. The mean baseline blood 25OHD level was 63 nmol/L; 2.3% were <25 nmol/L. Overall, we found that vitamin D supplementation did not affect the exacerbation risk (hazard ratio 1.08; 95%CI 0.84-1.39). Among those with baseline 25OHD <25 nmol/L, however, the hazard ratio was 0.11 (95%CI 0.02-0.51); p for interaction = 0.001. Although monthly vitamin D supplementation had no overall impact on risk of exacerbations of asthma or COPD, we found evidence of a probable benefit among those with severe vitamin D deficiency.

Nortriptyline for pain in knee osteoarthritis: a double-blind randomised controlled trial in New Zealand general practice.

BACKGROUND: Osteoarthritis (OA) of the knee is a common cause of chronic pain. Analgesics that are currently available have limited efficacy and may be poorly tolerated. Tricyclic antidepressants are used as analgesics for other chronic conditions, but they have not been evaluated as analgesics in OA. AIM: To investigate the analgesic efficacy of nortriptyline in people with knee OA. DESIGN AND SETTING: A two-arm, parallel-group, 1:1, double-blind, randomised, placebo-controlled trial in Christchurch, New Zealand. METHOD: Participants were recruited from orthopaedic outpatient clinics, primary care, and through public advertising. Adults with knee OA and a pain score of ≥20 points on the 50-point Western Ontario and McMaster University Osteoarthritis Index (WOMAC) pain subscale were randomised to receive either nortriptyline or identical placebo for 14 weeks. The primary outcome was knee pain at 14 weeks measured using the WOMAC pain subscale. Secondary outcomes included: function; stiffness; non-steroidal anti-inflammatory drug, opioid, and/or paracetamol use; each participant's global assessment; and adverse effects at 14 weeks. RESULTS: Of the 205 randomised participants, 201 (98.0%) completed follow-up at 14 weeks. The baseline-adjusted mean WOMAC pain subscale score at week 14 was 6.2 points lower (95% confidence interval = -0.26 to 12.6, P = 0.06) in the nortriptyline arm versus the placebo arm. Differences in secondary outcomes generally favoured the nortriptyline arm, but were small and unlikely to be clinically relevant. However, the following were all more commonly reported by participants taking nortriptyline than those taking a placebo: dry mouth (86.9% versus 51.0%, respectively, P<0.001), constipation (58.6% versus 30.4%, respectively, P<0.001), and sweating (31.3% versus 20.6%, respectively, P = 0.033). CONCLUSION: This study suggests nortriptyline does not significantly reduce pain in people with knee OA. The adverse effect profile was as expected.

What factors modify the effect of monthly bolus dose vitamin D supplementation on 25-hydroxyvitamin D concentrations?

The increasing use of vitamin D supplements has stimulated interest in identifying factors that may modify the effect of supplementation on circulating 25-hydroxyvitamin D (25(OH)D) concentrations. Such information is of potential interest to researchers, clinicians and patients when deciding on bolus dose of vitamin D supplementation. We carried out a large randomized controlled trial of 5110 adults aged 50-84 years, of European/Other (84%), Polynesian (11%) and Asian (5%) ethnicity, to whom we gave a standard dose of vitamin D3 supplements (200,000 IU initially, then 100,000 IU monthly) which was taken with high adherence. All participants provided a baseline blood sample, and follow-up blood samples were collected at 6 months and annually for 3 years in a random sample of 441 participants, and also at 2 years in 413 participants enrolled in a bone density sub-study. Serum 25(OH)D was measured by LC/MSMS. Mixed model analyses were carried out on all 854 participants providing follow-up blood samples in multivariable models that included age, sex, ethnicity, body mass index (kg/m2), tobacco smoking, alcohol intake, physical activity, sun exposure, season, medical prescription of high-dose vitamin D3 (Cal.D.Forte tablets), asthma/COPD and the study treatment (vitamin D or placebo). The adjusted mean difference in 25(OH)D in the follow-up points between vitamin D supplementation and placebo groups was inversely related (all p for interaction <0.05) to baseline 25(OH)D, BMI, and hours of sun exposure, and higher in females, elders, and those with high frequency of alcohol, medical prescription of vitamin D, and asthma/COPD. The mean difference was not significantly related to ethnicity (p = 0.12), tobacco (p = 0.34), and vigorous activity (p = 0.33). In summary, these data show that vitamin D status, BMI, sun exposure hours, sex and asthma/COPD modify the 25(OH)D response to vitamin D supplementation. By contrast, ethnicity, tobacco smoking, and vigorous activity do not.

Effect of Monthly High-Dose Vitamin D Supplementation on Acute Respiratory Infections in Older Adults: A Randomized Controlled Trial.

BACKGROUND: Although adults with low vitamin D status are at increased risk of acute respiratory infection (ARI), randomized controlled trials of vitamin D supplementation have provided inconsistent results. METHODS: We performed a randomized, double-blinded, placebo-controlled trial of 5110 adults aged 50-84 years. In 2011-2012, participants were randomized to an initial oral dose of 200 000 IU vitamin D3 followed by 100 000 IU monthly (n = 2558) or placebo (n = 2552) until late 2013 (median follow-up, 1.6 years). Participants reported upper and lower ARIs on monthly questionnaires. Cox models analyzed time to first ARI (upper or lower) by treatment group. RESULTS: Participants' mean age was 66 years and 58% were male; 83% were of European/other ethnicity, with the rest Maori, Polynesian, or South Asian. Mean (SD) baseline blood 25-hydroxyvitamin D [25(OH)D] level was 63 (24) nmol/L; 25% were <50 nmol/L. In a random sample (n = 441), vitamin D supplementation increased mean 25(OH)D to 135 nmol/L at 3 years, while those on placebo remained at 63 nmol/L. During follow-up, 3737 participants reported ≥1 ARI: 74.1% in the vitamin D group versus 73.7% in the placebo group. The hazard ratio for vitamin D compared with placebo was 1.01 (95% CI, 0.94, 1.07). Similar results were seen in most subgroups, including those with baseline 25(OH)D <50 nmol/L and in analyses of the upper/lower components of the ARI outcome. CONCLUSIONS: Monthly high-dose vitamin D supplementation does not prevent ARI in older adults with a low prevalence of profound vitamin D deficiency at baseline. Whether effects of daily or weekly dosing differ requires further study. CLINICAL TRIALS REGISTRATION: Australian New Zealand Clinical Trials Registry, identifier ACTRN12611000402943.

Monthly high-dose vitamin D supplementation does not increase kidney stone risk or serum calcium: results from a randomized controlled trial.

BACKGROUND: A growing number of randomized controlled trials (RCTs) are investigating the potential health benefits of high-dose vitamin D supplementation. However, there are limited RCT data on the safety of calcium-related adverse effects. OBJECTIVE: We investigated the incidence of kidney stone and hypercalcemia events in a large, population-based RCT of vitamin D supplementation. DESIGN: The Vitamin D Assessment (ViDA) study was a randomized, double-blind, placebo-controlled trial of vitamin D supplementation in 5110 participants in Auckland, New Zealand. This trial investigated the impact of monthly 100,000 IU vitamin D3 supplementation over several years on cardiovascular events, respiratory infections, and falls/fractures. Participants provided information about recent kidney stone events in regular questionnaires sent to them with study capsules. Hospitalization data for kidney stones were collected from health authorities. Serum calcium was measured in an 8% subsample of participants who returned annually for blood tests. HRs of time to the first kidney stone event were calculated by Cox regression. RESULTS: During a median follow-up of 3.3 y, 158 participants reported a kidney stone event (76 vitamin D, 82 placebo). The HR of reporting the first kidney stone event was 0.90 (95% CI: 0.66, 1.23; P = 0.51) for participants in the vitamin D arm compared with the placebo arm. There were 18 urolithiasis events in the hospitalization records: 7 in the vitamin D arm and 11 from the placebo arm. The HR to the first hospitalization urolithiasis event was 0.62 (95% CI: 0.24, 1.26; P = 0.30) in the vitamin D arm compared with the placebo arm. From the subsample annual blood test, there was no case of hypercalcemia in the vitamin D arm, compared with 1 in the placebo arm. CONCLUSION: Over a median of 3.3 y, monthly supplementation with 100,000 IU vitamin D3 did not affect the incidence rate of kidney stone events, or hypercalcemia. This study was registered at clinicaltrials.gov as ACTRN12611000402943.

Cross-sectional associations of vitamin D status with asthma prevalence, exacerbations, and control in New Zealand adults.

BACKGROUND: Previous studies, mostly with children, have reported inconsistent findings on the associations of vitamin D status with asthma prevalence, exacerbations, and control. Because of limited research with adults, we examined these associations in a large community-based sample of New Zealand adults. METHODS: 5110 participants, aged 50-84 years, were recruited from the community into a clinical trial of vitamin D supplementation. The current analysis is based on baseline blood sample collection to measure serum 25-hydroxyvitamin D (25(OH)D), which was deseasonalized for data analyses; and baseline asthma assessment, which included questions on asthma prevalence, urgent medical care for asthma in the previous 12 months, and control of asthma symptoms in the previous 4 weeks. RESULTS: 702 (13.2%) of 5088 participants reported having doctor-diagnosed asthma. There was no difference in mean (SE) 25(OH)D concentration between participants with and without asthma: 66 (0.9) and 66 (0.4) nmol/L, respectively, adjusting for sex (p = 0.71). However, in multivariable analyses restricted to participants who reported having asthma, mean (SE) 25(OH)D concentration was 6.3 (2.6) nmol/L lower in those who reported having urgent medical care for asthma in the previous 12 months compared to others (p = 0.02), and 10.4 (3.9) nmol/L lower in those with very poor asthma control compared to those who were well-controlled (p = 0.03). CONCLUSION: These cross-sectional results suggest that asthmatic adults with lower vitamin D status are more likely to receive urgent asthma medical care and to experience poor asthma control. Clinical trials are needed to determine the role of vitamin D supplementation in asthma management.

Association between serum 25-hydroxyvitamin D levels and self-reported chronic pain in older adults: A cross-sectional analysis from the ViDA study.

Chronic pain is a major contributor to the global burden of disability. Prior studies on the association between serum 25-hydroxyvitamin D (25(OH)D) levels and chronic pain have yielded mixed results. The Vitamin D Assessment study, a large randomized controlled trial from New Zealand, offered the opportunity to examine this association in data collected at baseline in all participants, and among those with arthritis or depression. A total of 5110 participants aged 50-84 years were recruited from community general practices. Chronic pain (lasting ≥6 months) and other baseline characteristics were collected at baseline interview. Serum 25(OH)D concentration was measured by liquid chromatography-tandem mass spectrometry. Associations between 25(OH)D levels and chronic pain were explored using multivariable log-binomial regression to estimate relative risks (RRs). Out of 5049 participants with complete data, 871 (17%) reported having this clinical outcome, and 1254 (25%) had a 25(OH)D concentration <50 nmol/L. There was no significant association between 25(OH)D and chronic pain, with vitamin D status categorized in four groups: <25.0, 25.0-49.9, 50.0-74.9, and ≥75.0 nmol/L (the highest group as reference). The unadjusted RRs were 1.09, 1.10, and 1.08, respectively (Ptrend = 0.24). Adjustment for demographics, lifestyle, BMI, medical history, prescription of analgesics and vitamin D supplements did not change this finding. Similar non-significant results were observed in participants with arthritis (n = 1732) or depression (n = 528). In this multi-ethnic, community-selected sample of older adults in New Zealand, serum 25(OH)D levels were not associated with chronic pain. These results do not support a role for low vitamin D status in the prevalence of chronic pain in older adults.

Monthly High-Dose Vitamin D Supplementation and Cancer Risk: A Post Hoc Analysis of the Vitamin D Assessment Randomized Clinical Trial.

Importance: Previous randomized clinical trials have reported inconsistent results on the effect of vitamin D supplementation on cancer incidence. Objective: To examine whether high-dose vitamin D supplementation received monthly, without calcium, is associated with a reduction in cancer incidence and cancer mortality in the general population. Design, Setting, and Participants: This is a post hoc analysis of data from the Vitamin D Assessment (ViDA) study, a randomized, double-blind, placebo-controlled trial that recruited participants from family practices and community groups in Auckland, New Zealand, from April 5, 2011, through November 6, 2012, with follow-up completed December 31, 2015. Participants were adult community residents aged 50 to 84 years. Of 47 905 adults invited from family practices and 163 from community groups, 5110 participants were randomized to receive vitamin D3 (n = 2558) or placebo (n = 2552). Two participants withdrew consent, and all others (n = 5108) were included in the primary analysis. Data analysis was by intention to treat. Interventions: Oral vitamin D3, in an initial bolus dose of 200 000 IU and followed by monthly doses of 100 000 IU, or placebo for a median of 3.3 years (range, 2.5-4.2 years). Main Outcomes and Measures: Post hoc primary outcome was the number of all primary invasive and in situ malignant neoplasms (excluding nonmelanoma skin cancers) diagnosed from randomization until the study medication was discontinued on July 31, 2015. Results: Of the 5108 participants included in the analysis, the mean (SD) age was 65.9 (8.3) years, 58.1% were male, and 4253 (83.3%) were of European or another race/ethnicity, with the remainder being Polynesian or South Asian. Mean (SD) baseline deseasonalized 25-hydroxyvitamin D concentration was 26.5 (9.0) ng/mL. In a random sample of 438 participants, the mean follow-up 25-hydroxyvitamin D concentration consistently was greater than 20 ng/mL higher in the vitamin D group than in the placebo group. The primary outcome of cancer comprised 328 total cases of cancer (259 invasive and 69 in situ malignant neoplasms) and occurred in 165 of 2558 participants (6.5%) in the vitamin D group and 163 of 2550 (6.4%) in the placebo group, yielding an adjusted hazard ratio of 1.01 (95% CI, 0.81-1.25; P = .95). Conclusions and Relevance: High-dose vitamin D supplementation prescribed monthly for up to 4 years without calcium may not prevent cancer. This study suggests that daily or weekly dosing for a longer period may require further study. Trial Registration: anzctr.org.au Identifier: ACTRN12611000402943.

Effects of vitamin D supplementation on adherence to and persistence with long-term statin therapy: Secondary analysis from the randomized, double-blind, placebo-controlled ViDA study.

BACKGROUND AND AIMS: Long-term statin use increases survival. However, the adherence to and persistence with statin use are challenging and this influences the success of statin treatment. Our aim was to explore if monthly vitamin D supplementation (100,000-IU) improves the adherence to and persistence with long-term statin use in older adults. METHODS: We conducted a secondary analysis of a trial comparing data on dispensed statin prescriptions, between participants allocated to vitamin D supplementation or placebo, for those taking statin therapy. Primary outcomes were defined as adherence to (proportion of days covered by prescriptions ≥80%) and persistence (non-discontinuation of the statin therapy following an allowed 30 days gap between refills) with all statins over a 24-month measurement period of statin therapy. Secondary outcomes were defined as adherence and persistence at other measurement periods for all types of statins and for individual statins. RESULTS: Overall, 2494 participants were on long-term statins at follow-up (vitamin D = 1243, placebo = 1251). Compared with placebo, monthly vitamin D supplementation did not improve the proportion with adherence (risk ratio: 1.01, p=0.62), but improved the persistence probability of taking all statins after 24 months (hazard ratio: 1.15, p=0.02). In further analyses, significant differences were observed in the adherence to simvastatin, the first-line statin therapy. CONCLUSIONS: Monthly vitamin D supplementation improved persistence with statins use over a 24-month measurement period in older adults on long-term statin therapy, especially for participants on simvastatin. The role of vitamin D supplementation as an adjunct therapy for patients on long-term statins merits further investigation.

Monthly vitamin D supplementation, pain, and pattern of analgesic prescription: secondary analysis from the randomized, double-blind, placebo-controlled Vitamin D Assessment study.

Observational studies suggest that vitamin D deficiency is associated with higher risk of pain. However, evidence on the effect of vitamin D supplementation on pain is limited and contradictory. The aim of this study was to compare the effect of monthly high-dose vitamin D supplementation on a pain impact questionnaire (PIQ-6) score and prescription of analgesics in the general population. We performed a randomized, double-blind, placebo-controlled trial of 5108 community-dwelling participants, aged 50 to 84 years, who were randomly assigned to receive monthly 100,000-IU capsules of vitamin D3 (n = 2558) or placebo (n = 2550) for a median of 3.3 years. The PIQ-6 was administered at baseline, year 1, and final follow-up. Analgesic prescription data were collected from Ministry of Health. There was no difference in mean PIQ-6 score at the end of follow-up (adjusted mean difference: 0.06; P = 0.82) between the vitamin D (n = 2041) and placebo (n = 2014) participants. The proportion of participants dispensed one or more opioids was similar in the vitamin D group (n = 559, 21.9%) compared with placebo (n = 593, 23.3%); the relative risk (RR) adjusted for age, sex, and ethnicity was 0.94 (P = 0.24). Similar results were observed for dispensing of nonsteroidal anti-inflammatory drugs (RR = 0.94; P = 0.24) and other nonopioids (RR = 0.98; P = 0.34). Focusing on vitamin D deficient participants (<50 nmol/L, 24.9%), there was a lower risk of dispensing nonsteroidal anti-inflammatory drugs in the vitamin D group compared with placebo (RR = 0.87; P = 0.009); all other subgroup analyses were not significant. Long-term monthly high-dose vitamin D supplementation did not improve mean PIQ-6 score or reduce analgesic dispensing in the general population.

Effect of Monthly, High-Dose, Long-Term Vitamin D on Lung Function: A Randomized Controlled Trial.

Although observational studies suggest positive vitamin D-lung function associations, randomized trials are inconsistent. We examined effects of vitamin D supplementation on lung function. We recruited 442 adults (50-84 years, 58% male) into a randomized, double-blinded, placebo-controlled trial. Participants received, for 1.1 years (median; range = 0.9-1.5 years), either (1) vitamin D3 200,000 IU, followed by monthly 100,000 IU doses (n = 226); or (2) placebo monthly (n = 216). At baseline and follow-up, spirometry yielded forced expiratory volume in 1 s (FEV1; primary outcome). Mean (standard deviation) 25-hydroxyvitamin D increased from 61 (24) nmol/L at baseline to 119 (45) nmol/L at follow-up in the vitamin D group, but was unchanged in the placebo group. There were no significant lung function improvements (vitamin D versus placebo) in the total sample, vitamin D-deficient participants or asthma/chronic obstructive pulmonary disease (COPD) participants. However, among ever-smokers (n = 217), the mean (95% confidence interval) FEV1 increase in the vitamin D versus placebo was 57 (4, 109) mL (p = 0.03). FEV1 increases were larger among vitamin D-deficient ever-smokers (n = 54): 122 (8, 236) mL (p = 0.04). FEV1 improvements were largest among ever-smokers with asthma/COPD (n = 60): 160 (53, 268) mL (p = 0.004). Thus, vitamin D supplementation did not improve lung function among everyone, but benefited ever-smokers, especially those with vitamin D deficiency or asthma/COPD.