Simon Spedding - Academia.edu (original) (raw)

Papers by Simon Spedding

Research paper thumbnail of Critical shortage of injectable thiamine in Australia

The Medical journal of Australia, Jan 15, 2004

Research paper thumbnail of Does Vitamin D Sufficiency Equate to a Single Serum 25-Hydroxyvitamin D Level or Are Different Levels Required for Non-Skeletal Diseases?

Nutrients, 2013

Objective: Clarify the concept of vitamin D sufficiency, the relationship between efficacy and vi... more Objective: Clarify the concept of vitamin D sufficiency, the relationship between efficacy and vitamin D status and the role of Vitamin D supplementation in the management of non-skeletal diseases. We outline reasons for anticipating different serum vitamin D levels are required for different diseases. Method: Review the literature for evidence of efficacy of supplementation and minimum effective 25-hydroxyvitamin D (25-OHD) levels in non-skeletal disease. Results: Evidence of efficacy of vitamin supplementation is graded according to levels of evidence. Minimum effective serum 25-OHD levels are lower for skeletal disease, e.g., rickets (25 nmol/L), osteoporosis and fractures (50 nmol/L), than for premature mortality (75 nmol/L) or non-skeletal diseases, e.g., depression (75 nmol/L), diabetes and cardiovascular disease (80 nmol/L), falls and respiratory infections (95 nmol/L) and cancer (100 nmol/L). Conclusions: Evidence for the efficacy of vitamin D supplementation at serum 25-OHD levels ranging from 25 to 100 nmol/L has been obtained from trials with vitamin D interventions that change vitamin D status by increasing serum 25-OHD to a level consistent with sufficiency for that disease. This evidence supports the hypothesis that just as vitamin D metabolism is tissue dependent, so the serum levels of 25-OHD signifying deficiency or sufficiency are disease dependent.

Research paper thumbnail of Seasonal effects on vitamin D status influence outcomes of lifestyle intervention in overweight and obese women with polycystic ovary syndrome

Fertility and Sterility, 2013

Objective: To investigate the effect of undertaking lifestyle interventions during periods of sea... more Objective: To investigate the effect of undertaking lifestyle interventions during periods of seasonal change on vitamin D status and health outcomes in overweight/obese women with polycystic ovary syndrome (PCOS). Design: Retrospective, unplanned secondary analysis of two cohorts during different seasons. Setting: Outpatient clinical research unit. Patient(s): Fifty overweight/obese women with PCOS. Intervention(s): Twenty-week lifestyle modification program (Clinical Trials registration no.: ACTRN12606000198527); one cohort started in winter and finished in summer, and one started in summer and finished in winter. Main Outcome Measure(s): 25-Hydroxyvitamin D (25OH-D), weight, waist circumference (WC), body composition, cardiovascular disease (CVD) risk factors, and menstrual cycle length. Result(s): Baseline 25OH-D levels were 27.6 AE 9.0 nmol/L. The winter cohort had lower 25OH-D levels at baseline, which increased over 20 weeks, whereas the summer cohort started with higher levels which decreased. Changes in 25OH-D were inversely correlated with changes in WC and cholesterol when controlling for baseline values, such that increases in 25OH-D were associated with greater reductions in WC and cholesterol. Conclusion(s): Obesity and CVD risk profiles improved in vitamin D-deficient women with PCOS after a 20-week lifestyle intervention during which vitamin D status improved with seasonal change.

Research paper thumbnail of Vitamin D in the aetiology and management of polycystic ovary syndrome

Clinical Endocrinology, 2012

Vitamin D deficiency is common in women with polycystic ovary syndrome (PCOS), with the 67-85% of... more Vitamin D deficiency is common in women with polycystic ovary syndrome (PCOS), with the 67-85% of women with PCOS having serum concentrations of 25-hydroxy vitamin D (25OHD) <20 ng/ml. Vitamin D deficiency may exacerbate symptoms of PCOS, with observational studies showing lower 25OHD levels were associated with insulin resistance, ovulatory and menstrual irregularities, lower pregnancy success, hirsutism, hyperandrogenism, obesity and elevated cardiovascular disease risk factors. There is some, but limited, evidence for beneficial effects of vitamin D supplementation on menstrual dysfunction and insulin resistance in women with PCOS. Vitamin D deficiency may play a role in exacerbating PCOS, and there may be a place for vitamin D supplementation in the management of this syndrome, but current evidence is limited and additional randomized controlled trials are required to confirm the potential benefits of vitamin D supplementation in this population.

Research paper thumbnail of Systematic assessment of clinical practice guidelines for the management of chronic obstructive pulmonary disease

Respiratory Medicine, 2003

Objective: To systematically evaluate the quality of the development of guidelines for the manage... more Objective: To systematically evaluate the quality of the development of guidelines for the management of chronic obstructive pulmonary disease (COPD). Methodology: MEDLINE and Excerpta Medica search for published guidelines, followed by independent evaluation by two reviewers, according to previously reported guideline development quality criteria, on a three-point scale. Results: Five national COPD guidelines and two international COPD guidelines were retrieved. Reviewers demonstrated good inter-observer agreement in assessing the 10 combined guideline development criteria for the seven guidelines [k = 0.66].Guidelines were only partly multi-disciplinary, with little or no consumer input, were up to 48 pages in length, and often lacked practical summaries or management flow charts which could have facilitatedretrieval of keymanagementrecommendations. Almost allthe papers were based upon a consensus approach, rather than evidence based, and methods of resolution of differences of opinion were not stated. Patient outcomes, ethical and medico-legal implications were not addressed and six of the guidelines were sponsored directly or indirectly by a single drug company.Conclusions: In spite of COPD guidelines being reported by major national bodies for over a decade now, most fail to meet important criteria for high-quality guideline development, and evaluation of clinical impact remains undetermined. r

Research paper thumbnail of Critical shortage of injectable thiamine in Australia

The Medical journal of Australia, Jan 15, 2004

Research paper thumbnail of Does Vitamin D Sufficiency Equate to a Single Serum 25-Hydroxyvitamin D Level or Are Different Levels Required for Non-Skeletal Diseases?

Nutrients, 2013

Objective: Clarify the concept of vitamin D sufficiency, the relationship between efficacy and vi... more Objective: Clarify the concept of vitamin D sufficiency, the relationship between efficacy and vitamin D status and the role of Vitamin D supplementation in the management of non-skeletal diseases. We outline reasons for anticipating different serum vitamin D levels are required for different diseases. Method: Review the literature for evidence of efficacy of supplementation and minimum effective 25-hydroxyvitamin D (25-OHD) levels in non-skeletal disease. Results: Evidence of efficacy of vitamin supplementation is graded according to levels of evidence. Minimum effective serum 25-OHD levels are lower for skeletal disease, e.g., rickets (25 nmol/L), osteoporosis and fractures (50 nmol/L), than for premature mortality (75 nmol/L) or non-skeletal diseases, e.g., depression (75 nmol/L), diabetes and cardiovascular disease (80 nmol/L), falls and respiratory infections (95 nmol/L) and cancer (100 nmol/L). Conclusions: Evidence for the efficacy of vitamin D supplementation at serum 25-OHD levels ranging from 25 to 100 nmol/L has been obtained from trials with vitamin D interventions that change vitamin D status by increasing serum 25-OHD to a level consistent with sufficiency for that disease. This evidence supports the hypothesis that just as vitamin D metabolism is tissue dependent, so the serum levels of 25-OHD signifying deficiency or sufficiency are disease dependent.

Research paper thumbnail of Seasonal effects on vitamin D status influence outcomes of lifestyle intervention in overweight and obese women with polycystic ovary syndrome

Fertility and Sterility, 2013

Objective: To investigate the effect of undertaking lifestyle interventions during periods of sea... more Objective: To investigate the effect of undertaking lifestyle interventions during periods of seasonal change on vitamin D status and health outcomes in overweight/obese women with polycystic ovary syndrome (PCOS). Design: Retrospective, unplanned secondary analysis of two cohorts during different seasons. Setting: Outpatient clinical research unit. Patient(s): Fifty overweight/obese women with PCOS. Intervention(s): Twenty-week lifestyle modification program (Clinical Trials registration no.: ACTRN12606000198527); one cohort started in winter and finished in summer, and one started in summer and finished in winter. Main Outcome Measure(s): 25-Hydroxyvitamin D (25OH-D), weight, waist circumference (WC), body composition, cardiovascular disease (CVD) risk factors, and menstrual cycle length. Result(s): Baseline 25OH-D levels were 27.6 AE 9.0 nmol/L. The winter cohort had lower 25OH-D levels at baseline, which increased over 20 weeks, whereas the summer cohort started with higher levels which decreased. Changes in 25OH-D were inversely correlated with changes in WC and cholesterol when controlling for baseline values, such that increases in 25OH-D were associated with greater reductions in WC and cholesterol. Conclusion(s): Obesity and CVD risk profiles improved in vitamin D-deficient women with PCOS after a 20-week lifestyle intervention during which vitamin D status improved with seasonal change.

Research paper thumbnail of Vitamin D in the aetiology and management of polycystic ovary syndrome

Clinical Endocrinology, 2012

Vitamin D deficiency is common in women with polycystic ovary syndrome (PCOS), with the 67-85% of... more Vitamin D deficiency is common in women with polycystic ovary syndrome (PCOS), with the 67-85% of women with PCOS having serum concentrations of 25-hydroxy vitamin D (25OHD) <20 ng/ml. Vitamin D deficiency may exacerbate symptoms of PCOS, with observational studies showing lower 25OHD levels were associated with insulin resistance, ovulatory and menstrual irregularities, lower pregnancy success, hirsutism, hyperandrogenism, obesity and elevated cardiovascular disease risk factors. There is some, but limited, evidence for beneficial effects of vitamin D supplementation on menstrual dysfunction and insulin resistance in women with PCOS. Vitamin D deficiency may play a role in exacerbating PCOS, and there may be a place for vitamin D supplementation in the management of this syndrome, but current evidence is limited and additional randomized controlled trials are required to confirm the potential benefits of vitamin D supplementation in this population.

Research paper thumbnail of Systematic assessment of clinical practice guidelines for the management of chronic obstructive pulmonary disease

Respiratory Medicine, 2003

Objective: To systematically evaluate the quality of the development of guidelines for the manage... more Objective: To systematically evaluate the quality of the development of guidelines for the management of chronic obstructive pulmonary disease (COPD). Methodology: MEDLINE and Excerpta Medica search for published guidelines, followed by independent evaluation by two reviewers, according to previously reported guideline development quality criteria, on a three-point scale. Results: Five national COPD guidelines and two international COPD guidelines were retrieved. Reviewers demonstrated good inter-observer agreement in assessing the 10 combined guideline development criteria for the seven guidelines [k = 0.66].Guidelines were only partly multi-disciplinary, with little or no consumer input, were up to 48 pages in length, and often lacked practical summaries or management flow charts which could have facilitatedretrieval of keymanagementrecommendations. Almost allthe papers were based upon a consensus approach, rather than evidence based, and methods of resolution of differences of opinion were not stated. Patient outcomes, ethical and medico-legal implications were not addressed and six of the guidelines were sponsored directly or indirectly by a single drug company.Conclusions: In spite of COPD guidelines being reported by major national bodies for over a decade now, most fail to meet important criteria for high-quality guideline development, and evaluation of clinical impact remains undetermined. r