Does testosterone influence the association between sleep and frailty in men: results from the European Male Aging Study

BACKGROUND

Previous studies have suggested an association between sleep disturbance and frailty. The mechanism is unknown, although it has been suggested that hormonal factors may play a role.

METHODS

The aim was to determine the association between sleep duration, sleep quality and frailty, and to determine whether testosterone influenced this association. Males aged 40-79 years were recruited from eight European centres to the European Male Aging Study (EMAS). Subjects completed an interviewer-assisted questionnaire including questions regarding sleep quality and duration. Sleep quality was scored 0-20 and categorised as 0-4, 5-9, 10-14, and 15-20, with higher scores indicating poorer quality. A 39-component frailty index (FI) was constructed. Total testosterone levels were measured. The association between sleep duration, sleep quality and the FI was assessed using negative binomial regression, with adjustment for putative confounders including testosterone level.

RESULTS

Two thousand three hundred ninety-three participants contributed data to the analysis. The mean age was 63.3 years and mean sleep duration was 7.01 h. The mean frailty index was 0.15. Mean testosterone levels declined with decreasing sleep quality. After adjustment, compared to those with a sleep score of 0-4, the FI was 57% (95% CI 38%, 78%) higher among those with a sleep score of 15-20. After adjustment compared to those with normal sleep duration (6-9 h), those with a short (< 6 h) and long (≥ 9 h) sleep duration had a 16% (95% CI 6%, 28%) and 11% (95% CI 0%, 23%) higher FI, respectively. Adjustment for testosterone did not influence the strength of either association.

CONCLUSION

Frailty is associated with impaired sleep quality and sleep duration. The association cannot, however, be explained by variation in testosterone levels.

Number of CAG repeats and mortality in middle aged and older men

DESIGN

The androgen receptor (AR) mediates peripheral effects of testosterone. Previous data suggests an association between the number of CAG repeats in exon-1 of the AR gene and AR transcriptional activity. The aim of this analysis was to determine the association between the number of AR CAG repeats and all-cause mortality in men and the influence of testosterone level on the association.

PATIENTS AND MEASUREMENTS

Follow-up data to 27 January 2018 were available for men aged 40-79 years recruited across six countries of the European Male Aging Study between 2003 and 2005. Cox proportional hazards modelling was used to determine the association between CAG repeat number/mortality. Results were expressed as hazard ratios (HR)/95% confidence intervals (CI).

RESULTS

One thousand nine hundred and seventy-seven men were followed up. Mean baseline age was 60 ± 11.1 years. Mean duration of follow-up was 12.2 years. At follow up 25.1% of men had died. CAG repeat length ranged from 6 to 39, with the highest proportion of CAG repeat number at 21 repeats (16.4%). In a multivariable model, compared to men with 22-23 AR CAG repeats: for men with <22 and >23 AR CAG HR, 95% CI for mortality were, <22 CAG repeats 1.17 (0.93-1.49) and >23 CAG repeats 1.14 (0.88-1.47). In a post-hoc analysis, the association was significant for men in the lowest tertile of baseline testosterone (<14.2 nmol/L) with >23 CAG repeats: in the adjusted model for <22 and >23 CAG repeats, respectively, 1.49 (0.97-2.27) and 1.68 (1.06-2.67) versus 22-23 repeats.

CONCLUSIONS

Our European-wide cohort data overall found no association of androgen receptor CAG repeat number and mortality in men. However, post hoc analysis suggested that an association might be present in men with lower baseline testosterone concentrations, which merits further investigation.

A Novel and Accurate Method for Estimating Deaths and Cases During Outbreaks of Infectious Diseases Including COVID-19

Introduction

Epidemiological modelling of infectious diseases plays an important role in driving public health policy. Commonly used models are described, including those based on exponential growth (Laplace and related distributions); susceptible-infected-removed; the Gompertz distribution; and the skew-reflected-Gompertz distribution. These are all sensitive to the timing of peak infection. The development of a novel method for forecasting the number of deaths occurring during epidemics of infectious diseases is described.

Methods

The mathematical development of the authors' novel asymmetric difference model is detailed in this paper. Its predictions for mortality rates associated with the COVID-19 pandemic for 14 countries were compared with the corresponding published mortality data.

Results

Forecasts by the asymmetric difference model of deaths from SARS-CoV-2 in different countries, actual recorded deaths to 30th June 2020, and corresponding errors included UK (42,700; 55,904; -24%); Poland (1490; 1444; +3%); Denmark (580; 605; -4%); Netherlands (6510; 6189; +5%); France (34,280; 29,836; +15%); Canada (1500; 8591; -78%); USA (44,540; 124,734; -64%); and Italy (22,020; 34,980; -37%). The model output was dependent upon forecast date accuracy for the peak of the disease outbreak. For Spain, the forecast date was one day early and for 10 (71%) countries the forecast peak occurred within seven days (inclusive) of the actual date.

Discussion

Mortality prediction by the asymmetric difference model is relatively accurate. Furthermore, this new model does not appear to be as unduly sensitive to the timing of peak infection as other models. Indeed, its prediction of peak infection also appears to be relatively accurate.

Association between psoriatic disease and lifestyle factors and comorbidities: cross-sectional analysis and Mendelian randomization

OBJECTIVES

To examine associations between PsA and psoriasis vs lifestyle factors and comorbidities by triangulating observational and genetic evidence.

METHODS

We analysed cross-sectional data from the UK Biobank (1836 PsA, 8995 psoriasis, 36 000 controls) to describe the association between psoriatic disease and lifestyle factors (including BMI and smoking) and 15 comorbidities [including diabetes and coronary artery disease (CAD)] using logistic models adjusted for age, sex and lifestyle factors. We applied bidirectional Mendelian randomization (MR) to genome-wide association data (3609 PsA and 7804 psoriasis cases, up to 1.2 million individuals for lifestyle factors and 757 601 for comorbidities) to examine causal direction, using the inverse-variance weighted method.

RESULTS

BMI was cross-sectionally associated with risk of PsA (OR 1.31 per 5 kg/m2 increase; 95% CI 1.26, 1.37) and psoriasis (OR 1.23; 1.20, 1.26), with consistent MR estimates (PsA OR 1.38; 1.14, 1.67; psoriasis OR 1.36; 1.18, 1.58). In both designs, smoking was more strongly associated with psoriasis than PsA. PsA and psoriasis were cross-sectionally associated with diabetes (OR 1.35 and 1.39, respectively) and CAD (OR 1.56 and 1.38, respective). Genetically predicted glycated haemoglobin (surrogate for diabetes) increased PsA risk (OR 1.18 per 6.7 mmol/mol increase; 1.02, 1.36) but not psoriasis. Genetic liability to PsA (OR 1.05; 1.003, 1.09) and psoriasis (OR 1.03; 1.001, 1.06) were associated with increased risk of CAD.

CONCLUSION

Observational and genetic evidence converge to suggest that BMI and glycaemic control are associated with increased psoriatic disease risk, while psoriatic disease is associated with increased CAD risk. Further research is needed to understand the mechanism of these associations.

The Impact of Frailty and Deprivation on the Likelihood of Receiving Primary Total Hip and Knee Arthroplasty among People with Hip and Knee Osteoarthritis

BACKGROUND

Among people with hip and knee osteoarthritis (OA), increasing deprivation is associated with reduced likelihood of receiving hip and knee arthroplasty (THA, TKA).

OBJECTIVES

To assess whether higher levels of frailty in the most deprived neighbourhoods explains the association between greater neighbourhood deprivation and reduced likelihood of receiving THA and TKA among people with hip and knee OA.

DESIGN

Longitudinal cohort study.

SETTING

Linked primary and secondary care electronic medical records and national mortality data.

PARTICIPANTS

104,913 individuals with incident hip OA and 216,420 with incident knee OA.

MEASUREMENTS

Frailty was assessed using a frailty index and categorised as fit, mild, moderate, and severe frailty. Neighbourhood deprivation was assessed using the index of multiple deprivation (IMD).

RESULTS

Compared to those in neighbourhoods in the least deprived quintile of IMD, those in neighbourhoods in the fourth and fifth quintile of IMD (most deprived), respectively, were less likely to receive THA, adjusted subhazard ratio (95% CI), 0.90 (0.87, 0.93) and 0.77 (0.74, 0.80), over a mean follow up of 4.4 years, with similar results for TKA. Higher levels of frailty at OA diagnosis were associated also with reduced likelihood of receiving THA and TKA. The association, however, between deprivation and likelihood of receiving THA and TKA could not be explained by increased levels of frailty among those living in the most deprived areas.

CONCLUSIONS

Further work is needed to understand why those in the most deprived areas are less likely to receive THA and TKA.

The association between lower socioeconomic position and functional limitations is partially mediated by obesity in older adults with symptomatic knee osteoarthritis: Findings from the English Longitudinal Study of Ageing

Objective

To assess the longitudinal associations of socioeconomic position (SEP) with functional limitations and knee joint replacement surgery (JRS) in people with symptomatic knee osteoarthritis (OA), and whether body mass index (BMI) mediated these relationships.

Methods

Data came from the English Longitudinal Study of Ageing, a national longitudinal panel study of adults aged ≥50 years. A total of 1,499 participants (62.3% female; mean age 66.5 (standard deviation (SD) 9.4) years; 47.4% obese) self-reporting an OA diagnosis and knee pain, with at least one BMI measurement were included. Mixed effect models estimated longitudinal associations of each SEP variable (education, occupation, income, wealth and deprivation index) and obesity (BMI ≥30.0 kg/m²) with repeated measures of functional limitations. Cox regression analyses estimated associations between SEP indicators and obesity at baseline and risk of knee JRS at follow-up. Structural equation modeling estimated any mediating effects of BMI on these relationships.

Results

Lower SEP and obesity at baseline were associated with increased odds of functional limitations in people with knee OA [e.g., difficulty walking 100 yards: no qualification vs. degree adjOR 4.33 (95% CI 2.20, 8.55) and obesity vs. no obesity adjOR 3.06 (95% CI 2.14, 4.37); similar associations were found for the other SEP indicators]. A small proportion of the association between lower SEP and functional limitations could be explained by BMI (6.2-12.5%). Those with lower income, lower wealth and higher deprivation were less likely to have knee JRS [e.g., adjHR most vs. least deprived 0.37 (95% CI 0.19, 0.73)]; however, no clear association was found for education and occupation. Obesity was associated with increased hazards of having knee JRS [adjHR 1.87 (95% CI 1.32, 2.66)]. As the direction of the associations for SEP and obesity with knee JRS were in opposite directions, no mediation analyses were performed.

Conclusions

Lower SEP was associated with increased odds of functional limitations but lower hazards of knee JRS among people with knee OA, potentially indicating underutilization of JRS in those with lower SEP. Obesity partially mediated the relationship between lower SEP and increased odds of functional limitations, suggesting adiposity as a potential interventional target.

The impact of frailty on patient-reported outcomes following hip and knee arthroplasty

AIM

to determine the impact of frailty on patient-reported outcomes following hip and knee arthroplasty.

METHODS

we used linked primary and secondary care electronic health records. Frailty was assessed using the electronic frailty index (categorised: fit, mild, moderate, severe frailty). We determined the association between frailty category and post-operative Oxford hip/knee score (OHS/OKS) using Tobit regression. We calculated the proportion of patients in each frailty category who achieved the minimally important change (MIC) in OHS (≥8 points) and OKS (≥7 points) and the proportion who reported a successful outcome (hip/knee problems either 'much better' or 'a little better' following surgery).

RESULTS

About 42,512 people who had a hip arthroplasty and 49,208 who had a knee arthroplasty contributed data. In a Tobit model adjusted for pre-operative OHS/OKS, age, sex and quintile of index of multiple deprivation, increasing frailty was associated with decreasing post-operative OHS and OKS, respectively, β-coefficient (95% CI) in severely frail versus fit, -6.97 (-7.44, -6.49) and - 5.88 (-6.28, -5.47). The proportion of people who achieved the MIC in OHS and OKS, respectively, decreased from 92 and 86% among fit individuals to 84 and 78% among those with severe frailty. Patient-reported success following hip and knee arthroplasty, respectively, decreased from 97 and 93% among fit individuals to 90 and 83% among those with severe frailty.

CONCLUSION

frailty adversely impacts on patient-reported outcomes following hip and knee arthroplasty. However, even among those with severe frailty, the large majority achieved the MIC in OHS/OKS and reported a successful outcome.

Increased Frailty in Individuals With Osteoarthritis and Rheumatoid Arthritis and the Influence of Comorbidity: An Analysis of the UK Biobank Cohort

OBJECTIVE

To determine the association between osteoarthritis (OA), rheumatoid arthritis (RA), and frailty and to determine whether comorbidities interact with OA and RA to further increase the likelihood of frailty.

METHODS

Participants of the UK Biobank age 40-69 years at baseline were included. Demographic, lifestyle, and clinical data were collected at baseline and follow-up in a subset. Frailty was assessed using a frailty index (FI) (continuous) and a modified frailty phenotype (robust, pre-frail, frail). The association between RA and OA and frailty at baseline and follow-up was assessed using multiple regression models. We looked at whether comorbidities, including cardiovascular disease, diabetes mellitus, chronic obstructive pulmonary disease, and depression interacted additively with OA and RA to increase the likelihood of frailty.

RESULTS

In total, 457,561 participants contributed data. Those with (versus without) RA (n = 4,894) and OA (n = 35,884), respectively, were more likely to be frail (adjusted relative risk ratio 10.7 [95% confidence interval (95% CI) 9.7, 11.7] and 3.4 [95% CI 3.3, 3.6]) and were more likely to have a higher FI at baseline. There was evidence of additive interaction between RA, OA, and common comorbidities increasing the occurrence of prevalent frailty. Among 25,163 participants included in longitudinal analysis, patients with RA (n = 202) and OA (n = 1,811) at baseline had an increased adjusted frailty incidence rate ratio (2.8 [95% CI 1.7, 4.6] and 1.7 [95% CI 1.3, 2.1], respectively) and also a higher FI during follow-up.

CONCLUSION

Individuals with RA and OA are more likely to have, or develop, frailty. Common comorbidities interact with OA and RA to further increase the likelihood of frailty.

1025 THE IMPACT OF DEPRIVATION AND FRAILTY ON THE LIKELIHOOD OF RECEIVING HIP AND KNEE ARTHROPLASTY DUE TO OSTEOARTHRITIS

Introduction

We determined the impact of deprivation and frailty at the time of diagnosis of hip or knee osteoarthritis (OA) on the likelihood of receiving total hip/knee arthroplasty (THA/TKA).

Method

We used routinely collected primary care data (Clinical Practice Research Datalink), linked to Hospital Episode Statistics. Frailty was assessed at the time of OA diagnosis using the electronic frailty index and categorised as fit, mild, moderate, and severe frailty. The association between quintile of index of multiple deprivation (IMD), frailty category and likelihood of receiving THA and TKA was assessed in separate Cox regression models, adjusted for year of OA diagnosis, age, and sex.

Results

104,672 individuals with hip OA and 220,714 with knee OA contributed data. Compared to those in the first quintile of IMD (least deprived), those in the fourth and fifth quintile of IMD (most deprived), respectively, were less likely to receive THA, hazard ratio (HR) (95% CI), 0.92 (0.89, 0.95) and 0.80 (0.77, 0.83), with similar results for TKA. Increasing frailty at OA diagnosis was associated with reduced likelihood of receiving THA/TKA. Compared to fit individuals, the HR (95% CI) for receiving THA and TKA, respectively among those with severe frailty was 0.42 (0.39, 0.45) and 0.57 (0.53, 0.61). Increasing deprivation was associated with increasing frailty at the time of hip/knee OA diagnosis, independent of age, sex, and year of OA diagnosis. However, those in the two most deprived quintiles were still less likely to receive THA/TKA after additionally adjusting for frailty category.

Conclusion

Increased deprivation and increased frailty category were associated with a lower likelihood of receiving THA/TKA among people with hip/knee OA. Increased frailty did not, however, explain the reduced likelihood of receiving THA/TKA among those living in the most deprived areas.

1024 THE IMPACT OF FRAILTY ON 30-DAY MORTALITY FOLLOWING PRIMARY HIP AND KNEE ARTHROPLASTY DUE TO OSTEOARTHRITIS

Introduction

We determined the association between frailty and 30-day mortality following total hip and knee arthroplasty (THA/TKA) due to osteoarthritis and also the impact of THA/TKA on 30-day mortality compared to a control population.

Method

We used linked primary and secondary care data and Office for National Statistics mortality data. Frailty was assessed using the electronic frailty index and categorised as fit, mild, moderate, and severe frailty. The association between frailty and 30-day mortality following THA/TKA was assessed using Cox regression, adjusted for year of birth, sex, quintile of index of multiple deprivation and year of surgery. Mortality following THA/TKA was also compared to a control population who had osteoarthritis but no previous THA/TKA, matched on year of birth, sex, and quintile of index of multiple deprivation.

Results

103,563 cases who had a THA, 125,367 who had a TKA, and matched controls contributed data. Among those who had surgery, 30-day mortality increased with increasing frailty; adjusted hazard ratio (HR) (95% CI) among severely frail vs fit: following THA, 2.85 (1.84, 4.39); following TKA, 2.14 (1.29, 3.53). Compared to fit controls who did not have surgery, 30-day mortality was higher among fit people who had THA and TKA, respectively, adjusted HR 1.60 (1.15, 2.21) and 2.98 (1.81, 4.89). There was, however, no statistically significant difference in 30-day mortality among cases with mild, moderate and severe frailty compared to controls in the same frailty category.

Conclusion

Among people who had THA and TKA, 30-day mortality increased with increasing frailty. A healthy surgery (selection) effect may have impacted on the comparison of mortality among cases who had THA/TKA and controls who did not have surgery.

The impact of frailty on short-term mortality following primary total hip and knee arthroplasty due to osteoarthritis

BACKGROUND

We determined the association between frailty and short-term mortality following total hip and knee arthroplasty (THA/TKA) for osteoarthritis and also the impact of THA/TKA on short-term mortality compared with a control population.

METHODS

Frailty was assessed using a frailty index (categorised: fit, mild, moderate, severe frailty). The association between frailty and short-term mortality following THA/TKA was assessed using Cox regression. Mortality following THA/TKA was also compared with a control population with osteoarthritis but no previous THA/TKA, matched on year of birth, sex and quintile of index of multiple deprivation.

RESULTS

A total of 103,563 cases who had a THA, 125,367 who had a TKA and matched controls contributed. Among those who had surgery, mortality increased with increasing frailty; adjusted hazard ratio (HR) (95% CI) at 30 days in severely frail versus fit: following THA, 2.85 (1.84, 4.39) and following TKA, 2.14 (1.29, 3.53). The predicted probability of 30-day mortality following THA/TKA varied by age, sex and frailty: following THA, from 0.05% among fit women aged 60-64 years to 6.55% among men with severe frailty aged ≥90 years. All-cause 30-day mortality was increased in fit cases following THA and TKA, respectively, versus fit controls (adjusted HR (95% CI), 1.60 (1.15, 2.21) and 2.98 (1.81, 4.89)), though not among cases with mild, moderate or severe frailty versus controls in the same frailty category.

CONCLUSION

Short-term mortality increased with increasing frailty following THA/TKA. Comparison of mortality among cases and controls may be affected by a 'healthy surgery' selection effect.

514 FRAILTY IN OSTEOARTHRITIS AND THE INFLUENCE OF CO-MORBIDITY

Introduction

Risk factors for frailty, including low physical activity and chronic pain, are common among people with osteoarthritis. The aim of this analysis was to determine the association between osteoarthritis and frailty and to determine whether comorbidities interact additively with OA to increase the likelihood of frailty.

Methods

Men and women aged 40-69 years who contributed to the UK Biobank were analysed. Data about self-reported physician-diagnosed diseases was collected, as well physical measurements, including hand-grip strength. Frailty (robust, pre-frail, frail) was assessed using a modified frailty phenotype, comprising five components: low grip strength, slow walking speed, weight loss, low physical activity, and exhaustion. The association between osteoarthritis and the frailty phenotype was determined using negative binomial regression, adjusting for age, sex, body mass index, smoking status, and Townsend deprivation score. We calculated the attributable proportion of risk of frailty due to additive interaction between osteoarthritis and common co-morbidities (cardiovascular disease, diabetes, COPD, and depression).

Results

457,561 people were included, 35,884 (7.8%) had osteoarthritis. The adjusted relative risk ratio (95% CI) for pre-frailty and frailty (versus robust), respectively was higher among people with (versus without) osteoarthritis: 1.58 (1.54, 1.62) and 3.41 (3.26, 3.56). There was significant additive interaction between the presence of osteoarthritis and each of the co-morbidities considered in increasing risk of frailty, particularly diabetes (attributable proportion of risk due to additive interaction with osteoarthritis (95% CI)), 0.49 (0.42, 0.55), coronary heart disease 0.48 (0.41, 0.55), and depression 0.47 (0.41, 0.53).

Conclusions

Our results suggest that people with OA are at increased risk of pre-frailty and frailty. The mechanisms are not fully understood, though co-morbidity appears to contribute to the risk of frailty beyond the expected additivity of risk due to OA and co-morbidity. Early diagnosis and optimal management of co-morbidities in people with OA may be beneficial.

P093 Sleep characteristics and frailty in men: the influence of testosterone

Background/Aims 

Previous studies have suggested an association between sleep disturbance and frailty. The mechanism is unknown, though it has been suggested that hormonal factors may play a role. The aim of this analysis was to determine the association between sleep duration, sleep quality and frailty in middle age and older European men and the influence of testosterone on these associations.

Methods 

Men aged 40-79 years were recruited from population samples in eight European centres for participation in the European Male Age Study. Participants were interviewed and asked also to complete a questionnaire about sleep which included a question about average number of hours sleep per night and questions about sleep quality. Sleep quality was scored 0-20 with higher score indicating poor quality. A frailty index (FI) was constructed. Participants also had a single fasting morning venous blood sample taken and total testosterone measured using gas chromatography mass spectrometry. Using negative binomial regression we looked at the association between sleep duration, sleep quality and frailty (outcome; range 0-100) with the results adjusted for putative confounders and also testosterone level.

Results 

2,369 participants contributed data to the analysis. Mean sleep duration was 7.01 hours. 256 (10.7%) participants had sleep quality scores between 10 -14 and 101 (4.2%) participants’ scores were between 15 and 20. Mean (standard deviation) testosterone level was 16.4 (6.2) pmol/l and 14.7% of subjects had a low testosterone level (&lt;10.5pmol/l). After adjustment for age, centre, body mass index, depression, pain, alcohol intake and smoking, compared to those with a sleep score of 0-4, those with scores of 10-14 and 15-20 were more likely to have a higher frailty index (RR = 1.37; 95% CI 1.25,1.49) and (RR = 1.57; 95% CI 1.38, 1.78) respectively. Further adjustment for testosterone did not influence the strength of these associations. Compared to those with sleep 6-8 hours, those with less than 5 hours had a significantly higher FI (RR = 1.16; 95% CI 1.06, 1.28) and also those with a longer sleep duration (9 hours or more) had a significantly increased FI (RR = 1.11; 95% CI 1.00, 1.23). Further adjustment for testosterone did not influence the strength of these associations.

Conclusion 

Frailty is associated with impaired sleep quality and also sleep duration. The mechanism is unknown though cannot be explained by testosterone level.

Disclosure 

S.D. Sharma: None. M.J. Cook: None. D. Vanderschueren: None. L. Antoniou: None. E. Gielen: None. F.C. Wu: None. T.W. O’Neill: None.

O27 Frailty and co-morbidity in people with osteoarthritis and rheumatoid arthritis

Background/Aims 

People with osteoarthritis (OA) and rheumatoid arthritis (RA) are at increased risk of frailty, though the role of co-morbidities in contributing to frailty risk in these arthritides is uncertain. The aim of this study was i) to determine the association between common co-morbidities and frailty in OA and RA; and ii) to determine whether co-morbidities interact synergistically with OA and RA to increase the likelihood of frailty.

Methods 

A cross-sectional analysis of the UK Biobank data was carried out. In this national cohort of participants aged 40-69 years, self-reported physician-diagnosed diseases including OA, RA, and common co-morbidities (including hypertension, coronary heart disease, diabetes, stroke/TIA, chronic obstructive pulmonary disease (COPD), and depression) were recorded. Frailty was assessed using a modification of the frailty phenotype (FP), comprising five components: self-reported weight loss, exhaustion, low physical activity (international activity questionnaire), slow walking speed, and low hand-grip strength. Pre-frailty and frailty, was identified based on the presence of 1-2 and ≥3 of these components, respectively. Among participants with OA and RA at baseline, the likelihood of being pre-frail or frail (vs not frail) at baseline among people with (vs without) each of the co-morbidities was assessed using multinomial logistic regression. To determine whether co-morbidities interact synergistically with OA and RA to increase the likelihood of frailty, deviation from additivity of risk was estimated by calculating the attributable proportion (AP) of risk due to biological interaction. An AP &gt; 0 indicates positive (synergistic) biological interaction. Analyses were adjusted for age, sex, smoking status, BMI, and deprivation.

Results 

In total, 457,561 people were included in the analysis; 35,884 (7.8%) had OA and 4,894 (1.1%) had RA. Overall, the mean (SD) age was 56.5 (8.1) years and 54% were female. The overall prevalence of frailty was 3.4%. The prevalence of frailty was higher among those with OA (10.0%) and RA (18.6%). Each of the co-morbidities considered was associated with increased relative risk of pre-frailty and frailty particularly COPD in OA, relative risk ratio (95%CI): pre-frailty, 2.09 (1.80, 2.42) and frailty, 4.45 (3.71, 5.33) and stroke/TIA in RA: pre-frailty, 1.97 (1.18, 3.29) and frailty, 3.64 (2.11, 6.29). Most of the co-morbidities considered interacted synergistically with OA and RA to increase the risk of pre-frailty and frailty, particularly diabetes in OA, AP (95% CI): pre-frailty, 0.13 (0.04, 0.23) and frailty, 0.49 (0.42, 0.55) and stroke/TIA in RA: pre-frailty, 0.34 (0.003, 0.68) and frailty 0.60 (0.38, 0.82).

Conclusion 

Co-morbidity is associated with an increased occurrence of pre-frailty and frailty among people with OA and RA and interacts synergistically with OA and RA to increase the likelihood of pre-frailty and frailty.

Disclosure 

M.J. Cook: None. M. Lunt: None. S.M.M. Verstappen: None. T.W. O'Neill: None.

P094 Incidence of clinically diagnosed Paget’s disease of bone: evidence of a continuing decline

Background/Aims 

Evidence from the UK suggest that the incidence of Paget's disease of bone declined during the latter half of the last century with a decline also in the incidence of clinically apparent disease. We aimed to characterise the recent incidence of clinically diagnosed Paget’s disease of bone in the UK by age and sex among those aged &gt;18 years and, to determine whether the incidence has changed from 1999-2015.

Methods 

Incident cases of Paget’s disease during 1999-2015 were identified from the first recorded diagnostic code for Paget’s disease in the UK Clinical Practice Research Datalink (CPRD) database. Crude incidence was calculated for each year from 1999 to 2015 and, to account for changes in the distribution of age and sex over time within the CPRD, direct age- and sex-standardised incidence rates were calculated for each year. This was done by multiplying the crude incidence in each age-sex stratum by the age-sex stratum weight of the 1999 population of those at risk of developing Paget’s disease. We looked also at the incidence of disease by quintile of index of multiple deprivation and geographic region. Using Poisson regression, we looked at the influence of deprivation and geography on occurrence of the disease after adjustment for age and sex.

Results 

In total 3,592 incident cases of Paget’s disease were identified between 1999 and 2015. Overall the incidence increased with age and at all ages was greater in men than women. In men, and women, respectively, incidence increased from 0.074 and 0.037 per 10,000 per year at the age of 45-49 years to 6.3 and 3.7 per 10,000 per year at age of 85 years and older. When stratified by year, the age- and sex-standardised incidence fell from 0.75/10,000 person years in 1999 to 0.20/10,000 person years in 2015. Crude incidence (1999-2015) was slightly higher in those living in the most deprived areas (0.53/10,000 person years) compared to those in least deprived areas (0.43/10,000 person years). After adjustment for age and sex, compared to those in the highest quintile of index of multiple deprivation, those in the lowest quintile of index of multiple deprivation had over a 30% increased risk of disease. There was evidence also of geographic variation in the occurrence of disease with the highest incidence in the North West of England.

Conclusion 

The incidence of clinically diagnosed Paget’s disease has continued to decrease since 1999. The reason for the decline remains unknown, though the rapidity of change points to an alteration in one or more environmental determinants.

Disclosure 

M.J. Cook: None. S.R. Pye: None. W.G. Dixon: None. T.W. O'Neill: None.

Incidence of Paget's Disease of Bone in the UK: Evidence of a Continuing Decline

OBJECTIVES

To characterise the incidence of clinically diagnosed Paget's disease of bone in the UK during 1999-2015 and to determine variation in incidence of disease by age, sex, geography and level of deprivation.

METHODS

Incident cases of Paget's disease occurring between 1999-2015 were identified from primary care records. Overall crude incidence and incidence stratified by age and sex was calculated each year from 1999-2015. Direct age- and sex-standardised incidence was also calculated. We used Poisson regression to look at variation in incidence by deprivation and UK region.

RESULTS

3,592 incident cases of Paget's disease were identified between 1999-2015. Incidence increased with age and at all ages was greater in men than women. In women and men, respectively, crude incidence increased from 0.037 and 0.074 per 10 000 population per year among those aged 45-49 years to 3.7 and 6.3 per 10 000 population per year among those 85 years and older. Overall standardised incidence reduced from 0.75/10 000 person-years in 1999-0.20/10 000 person-years in 2015. After adjustment for age and sex, incidence was >30% higher in the most, compared with least deprived quintile of deprivation. There was evidence of geographic variation, with highest incidence in the North West of England, which persisted after adjustment for age, sex, and level of deprivation.

CONCLUSION

The incidence of clinically diagnosed Paget's disease has continued to decrease since 1999. The reason for the decline in incidence remains unknown though the rapidity of change points to an alteration in one or more environmental determinants.

Statins, bone biology and revision arthroplasty: review of clinical and experimental evidence

Osteoarthritis is a painful, disabling condition which is increasing in prevalence as a result of an ageing population. With no recognized disease-limiting therapeutics, arthroplasty of the hip and knee is the most common and effective treatment for lower limb osteoarthritis, however lower limb arthroplasty has a finite life-span and a proportion of patients will require revision arthroplasty. With increasing life expectancy and an increasing proportion of younger (<65 years) patients undergoing arthroplasty, the demand for revision arthroplasty after implant failure is also set to increase.

Statins are cholesterol-modulating drugs widely used for cardiovascular risk reduction which have been noted to have pleiotropic effects including potentially influencing arthroplasty survival. In vitro studies have demonstrated pleiotropic effects in human bone cells, including enhancement of osteoblastogenesis following simvastatin exposure, and in vivo studies have demonstrated that intraperitoneal simvastatin can increase peri-implant bone growth in rats following titanium tibial implant insertion. There is evidence that statins may also influence osseointegration, enhancing bone growth at the bone–implant interface, subsequently improving the functional survival of implants. Data from the Danish Hip Arthroplasty Registry and the Clinical Practice Research Datalink in the UK suggest a reduction in the risk of lower limb revision arthroplasty in statin ever-users versus never-users, and a time-dependent effect of statins in reducing the risk of revision. In this article we review the clinical and experimental evidence linking statins and risk of revision arthroplasty.

Peptide directed phthalocyanine-gold nanoparticles for selective photodynamic therapy of EGFR overexpressing cancers

Gold nanoparticles, covalently functionalised with the photosensitiser C11Pc and PEG, were actively targeted towards epidermal growth factor receptor overexpressing cancers using the peptide FITC-βAAEYLRK. Selective phototoxicity was observed at nanomolar concentrations with minimal dark toxicity.

Estimates for Lyme borreliosis infections based on models using sentinel canine and human seroprevalence data

Two models were developed to estimate Lyme borreliosis (LB) cases. One was based on the seroprevalence of Borrelia infections in human samples. This model used corrections for false negative and false positive results from published test sensitivity and specificity measures. A second model based on Borrelia infections in sentinel dogs was used to quantify the prevalence of Lyme disease Borrelia infections in humans; the reference baseline for this model was human and canine infections in Germany. A comparison of the two models is shown and differences discussed. The relationships between incidence, prevalence and total infection burden for LB were derived from published data and these were used in both models to calculate annual incidence, prevalence and total LB infections. The modelling was conservative and based on medical insurance records coded for erythema migrans. Linear model growth rates were used in place of the commonly adopted exponential growth. The mean of the two models was used to create estimates for various countries and continents. Examples from the analyses for LB estimated for 2018 include: incidence - USA 473,000/year, Germany 471,000/year, France 434,000/year and UK 132,000/year; prevalence - USA 2.4 million, Germany 2.4 million, France 2.2 million and UK 667,000; total infections - USA 10.1 million, Germany 10.0 million, France 9.3 million and UK 2.8 million. Estimates for the world for 2018 are: incidence 12.3 million/year; prevalence 62.1 million; and total infection burden 262.0 million. These figures are far higher than officially published data and reflect not only the underestimation of diagnosed cases, which is acknowledged by health agencies, but also undiagnosed and misdiagnosed cases.

Is the use of antibiotic-loaded bone cement associated with a lower risk of revision after primary total hip arthroplasty?

AIMS

The aim of this study was to investigate whether the use of antibiotic-loaded bone cement influenced the risk of revision surgery after primary total hip arthroplasty (THA) for osteoarthritis.

METHODS

The study involved data collected by the National Joint Registry (NJR) for England and Wales, Northern Ireland and the Isle of Man between 1 September 2005 and 31 August 2017. Cox proportional hazards were used to investigate the association between use of antibiotic-loaded bone cement and the risk of revision due to prosthetic joint infection (PJI), with adjustments made for the year of the initial procedure, age at the time of surgery, sex, American Society of Anesthesiologists (ASA) grade, head size, and body mass index (BMI). We looked also at the association between use of antibiotic-loaded bone cement and the risk of revision due to aseptic loosening or osteolysis.

RESULTS

The cohort included 418,857 THAs of whom 397,896 had received antibiotic-loaded bone cement and 20,961 plain cement. After adjusting for putative confounding factors, the risk of revision for PJI was lower in those in whom antibiotic-loaded bone cement was used (hazard ration (HR) 0.79; 95% confidence interval (CI) 0.64 to 0.98). There was also a protective effect on the risk of revision due to aseptic loosening or osteolysis, in the period of > 4.1 years after primary THA, HR 0.57, 95% CI 0.45, 0.72.

CONCLUSION

Within the limits of registry analysis, this study showed an association between the use of antibiotic-loaded bone cement and lower rates of revision due to PJI. The findings support the continued use of antibiotic-loaded bone cement in cemented THA. Cite this article: Bone Joint J 2020;102-B(8):997-1002.

Task-related functional magnetic resonance imaging activations in patients with acute and subacute mild traumatic brain injury: A coordinate-based meta-analysis

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ALE meta-analysis revealed functional activation differences in mTBI.

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Reduced activation identified within the right middle frontal gyrus.

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Suggests alteration of prefrontal region, associated with executive functioning.

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Need for addressing subject- and task-specific variation in future studies.

Task-based functional magnetic resonance imaging (fMRI) has been used to examine neuroanatomical and functional changes following mild traumatic brain injury (mTBI). Prior studies have lacked consistency in identifying common regions of altered neural activity during cognitive tasks. This may be partly due to differences in task paradigm, patient heterogeneity, and methods of fMRI analysis. We conducted a meta-analysis using an activation likelihood estimation (ALE) method to identify regions of differential brain activation in patients with mTBI compared to healthy controls. We included experiments that performed scans from acute to subacute time points post-injury. The seven included studies recruited a total sample of 174 patients with mTBIs and 139 control participants. The results of our coordinate based meta-analysis revealed a single cluster of reduced activation within the right middle frontal gyrus (MFG) that differentiated mTBI from healthy controls. We conclude that the cognitive impairments in memory and attention typically reported in mTBI patients may be associated with a deficit in the right MFG, which impacts the recruitment of neural networks important for attentional control.

The prevalence of co-morbidities and their impact on physical activity in people with inflammatory rheumatic diseases compared with the general population: results from the UK Biobank

Objectives

To compare the prevalence and incidence of chronic co-morbidities in people with inflammatory rheumatic and musculoskeletal diseases (iRMDs), and to determine whether the prevalent co-morbidities are associated with physical activity levels in people with iRMDs and in those without iRMDs.

Methods

Participants were recruited to the UK Biobank; a population-based cohort. Data were collected about demographics, physical activity, iRMDs (RA, PsA, AS, SLE) and other chronic conditions, including angina, myocardial infarction, stroke, hypertension, pulmonary disease, diabetes and depression. The standardized prevalence of co-morbidities in people with iRMDs was calculated. Cox regression was used to determine the relationship between the presence of an iRMD and an incident co-morbidity. The relationship between the presence (versus absence) of a (co-)morbidity and physical activity level (low, moderate, high) in people with iRMDs and in those without was assessed using multinomial logistic regression.

Results

A total of 488 991 participants were included. The estimated prevalence of each co-morbidity was increased in participants with an iRMD, compared with in those without, particularly for stroke in participants with SLE (standardized morbidity ratio (95% CI), 4.9 (3.6, 6.6). Compared with people with no iRMD and no morbidity, the odds ratios (95% CI) for moderate physical activity were decreased for: no iRMD and morbidity, 0.87 (0.85, 0.89); iRMD and no co-morbidity, 0.71 (0.64, 0.80); and iRMD and co-morbidity, 0.58 (0.54, 0.63).

Conclusion

Having a (co-)morbidity is associated with reduced physical activity in the general population, and to a greater extent in participants with an iRMD. Optimal management of both iRMDs and co-morbidities may help to reduce their impact on physical activity.

Effect of Timing and Duration of Statin Exposure on Risk of Hip or Knee Revision Arthroplasty: A Population-based Cohort Study

OBJECTIVES

To determine whether the timing and duration of statin exposure following total hip/knee arthroplasty (THA/TKA) influence the risk of revision arthroplasty.

METHODS

Subjects from the Clinical Practice Research Datalink, a large population-based clinical database, who had THA/TKA from 1988 to 2016, were included. Propensity score adjusted Cox regression models were used to determine the association between statin exposure and the risk of revision THA/TKA, (1) at any time, and (2) if first exposed 0-1, 1-5, or > 5 years following THA/TKA. We also investigated the effect of duration of statin exposure (< 1, 1-2, 2-3, 3-4, 4-5, > 5 yrs).

RESULTS

The study included 151,305 participants. There were 65,032 (43%) exposed to statins during followup and 3500 (2.3%) had revision arthroplasty. In a propensity score adjusted model, exposure to statins was associated with a reduced risk of revision arthroplasty (HR 0.82, 95% CI 0.75-0.90). Participants first exposed within 1 year and between 1 and 5 years following THA/TKA (vs unexposed) had a reduced risk of revision arthroplasty (HR 0.82, 95% CI 0.74-0.91 and HR 0.76, 95% CI 0.65-0.90, respectively). In relation to duration of statin therapy, participants exposed for more than 5 years in total (vs < 1 yr) had a reduced risk of revision (HR 0.74, 95% CI 0.62-0.88).

CONCLUSION

Statin therapy initiated up to 5 years following THA/TKA may reduce the risk of revision arthroplasty.

Fixed-target serial oscillation crystallography at room temperature

A fixed-target approach to high-throughput room-temperature serial synchrotron crystallography with oscillation is described. Patterned silicon chips with microwells provide high crystal-loading density with an extremely high hit rate. The microfocus, undulator-fed beamline at CHESS, which has compound refractive optics and a fast-framing detector, was built and optimized for this experiment. The high-throughput oscillation method described here collects 1-5° of data per crystal at room temperature with fast (10° s-1) oscillation rates and translation times, giving a crystal-data collection rate of 2.5 Hz. Partial datasets collected by the oscillation method at a storage-ring source provide more complete data per crystal than still images, dramatically lowering the total number of crystals needed for a complete dataset suitable for structure solution and refinement - up to two orders of magnitude fewer being required. Thus, this method is particularly well suited to instances where crystal quantities are low. It is demonstrated, through comparison of first and last oscillation images of two systems, that dose and the effects of radiation damage can be minimized through fast rotation and low angular sweeps for each crystal.

Towards optimisation of surface enhanced photodynamic therapy of breast cancer cells using gold nanoparticle–photosensitiser conjugates

Surface enhanced fluorescence of zinc pthalocyanine-functionalised gold nanoparticles leads to a remarkable enhancement in photodynamic efficiency and cell death.

Targeted photodynamic therapy of breast cancer cells using lactose-phthalocyanine functionalized gold nanoparticles

Gold nanoparticles (AuNPs), which have been widely used for the delivery of photosensitizers for photodynamic therapy (PDT) of cancer, can be dispersed in aqueous solutions improving the delivery of the hydrophobic photosensitizer into the body. Furthermore, the large surface of AuNPs can be functionalized with a variety of ligands, including proteins, nucleic acids and carbohydrates, that allow selective targeting to cancer tissue. In this study, gold nanoparticles were functionalized with a mixed monolayer of a zinc phthalocyanine and a lactose derivative. For the first time, a carbohydrate was used with a dual purpose, as the stabilizing agent of the gold nanoparticles in aqueous solutions and as the targeting agent for breast cancer cells. The functionalization of the phthalocyanine-AuNPs with lactose led to the production of water-dispersible nanoparticles that are able to generate singlet oxygen and effect cell death upon irradiation. The targeting ability of lactose of the lactose-phthalocyanine functionalized AuNPs was studied in vitro towards the galectin-1 receptor on the surface of breast cancer cells. The targeting studies showed the exciting potential of lactose as a specific targeting agent for galactose-binding receptors overexpressed on breast cancer cells.

Associations of muscle force, power, cross-sectional muscle area and bone geometry in older UK men

BACKGROUND

Ageing is associated with sarcopenia, osteoporosis, and increased fall risk, all of which contribute to increased fracture risk. Mechanically, bone strength adapts in response to forces created by muscle contractions. Adaptations can be through changes in bone size, geometry, and bending strength. Muscle mass is often used as a surrogate for muscle force; however, force can be increased without changes in muscle mass. Increased fall risk with ageing has been associated with a decline in muscle power-which is a measure of mobility. The aims of this study were as follows: (i) to investigate the relationship between muscle parameters in the upper and lower limbs with age in UK men and the influence of ethnicity on these relationships; (ii) to examine the relationships between jump force/grip strength/cross-sectional muscle area (CSMA) with bone outcomes at the radius and tibia.

METHODS

White European, Black Afro-Caribbean, and South Asian men aged 40-79 years were recruited from Manchester, UK. Cortical bone mineral content, cross-sectional area, cortical area, cross-sectional moment of inertia, and CSMA were measured at the diaphysis of the radius and tibia using peripheral quantitative computed tomography. Lower limb jump force and power were measured from a single two-legged jump performed on a ground-reaction force platform. Grip strength was measured using a dynamometer. Associations between muscle and bone outcomes was determined using linear regression with adjustments for age, height, weight, and ethnicity.

RESULTS

Three hundred and one men were recruited. Jump force was negatively associated with age; for every 10 year increase in age, there was a 4% reduction in jump force (P < 0.0001). There was a significant age-ethnicity interaction for jump power (P = 0.039); after adjustments, this was attenuated (P = 0.088). For every 10 year increase in age, grip strength decreased by 11%. Jump force was positively associated with tibial bone outcomes: a 1 standard deviation greater jump force was associated with significantly higher cortical bone mineral content 3.1%, cross-sectional area 4.2%, cortical area 3.4%, and cross-sectional moment of inertia 6.8% (all P < 0.001). Cross-sectional muscle area of the lower leg was not associated with tibial bone outcomes. Both grip strength and CSMA of the arm were positively associated, to a similar extent, with radius diaphyseal bone outcomes.

CONCLUSIONS

Jump force and power are negatively associated with age in UK men. In the lower limb, the measurement of jump force is more strongly related to bone outcomes than CSMA. It is important to consider jump force and power when understanding the aetiology of bone loss and mobility in ageing men.

Frailty and bone health in European men

Background

frailty is associated with an increased risk of fragility fractures. Less is known, however, about the association between frailty and bone health.

Methods

men aged 40-79 years were recruited from population registers in eight European centres for participation in the European Male Aging Study. Subjects completed a comprehensive assessment which included quantitative ultrasound (QUS) scan of the heel (Hologic-SAHARA) and in two centres, dual-energy bone densitometry (dual-energy x-ray absorptiometry, DXA). Frailty was defined based on an adaptation of Fried's phenotype criteria and a frailty index (FI) was constructed. The association between frailty and the QUS and DXA parameters was determined using linear regression, with adjustments for age, body mass index and centre.

Results

in total, 3,231 subjects contributed data to the analysis. Using the Fried categorisation of frailty, pre-frail and frail men had significantly lower speed of sound (SOS), broadband ultrasound attenuation (BUA) and quantitative ultrasound index (QUI) compared to robust men (P< 0.05). Similar results were seen using the FI after categorisation into 'high', 'medium' and 'low' levels of frailty. Using the Fried categorisation, frail men had lower femoral neck bone mineral density (BMD) compared to robust men (P < 0.05), but not lower lumbar spine BMD. Using the FI categorisation, a 'high' level of frailty (FI > 0.35) was associated with lower lumbar spine BMD (P < 0.05) when compared to those with low (FI < 0.2), but not lower femoral neck BMD. When analysed as a continuous variable, higher FI was linked with lower SOS, BUA and QUI (P < 0.05).

Conclusions

optimisation of bone health as well as prevention of falls should be considered as strategies to reduce fractures in frail older people.

Application of Bayesian decision-making to laboratory testing for Lyme disease and comparison with testing for HIV

In this study, Bayes' theorem was used to determine the probability of a patient having Lyme disease (LD), given a positive test result obtained using commercial test kits in clinically diagnosed patients. In addition, an algorithm was developed to extend the theorem to the two-tier test methodology. Using a disease prevalence of 5%-75% in samples sent for testing by clinicians, evaluated with a C6 peptide enzyme-linked immunosorbent assay (ELISA), the probability of infection given a positive test ranged from 26.4% when the disease was present in 5% of referrals to 95.3% when disease was present in 75%. When applied in the case of a C6 ELISA followed by a Western blot, the algorithm developed for the two-tier test demonstrated an improvement with the probability of disease given a positive test ranging between 67.2% and 96.6%. Using an algorithm to determine false-positive results, the C6 ELISA generated 73.6% false positives with 5% prevalence and 4.7% false positives with 75% prevalence. Corresponding data for a group of test kits used to diagnose HIV generated false-positive rates from 5.4% down to 0.1% indicating that the LD tests produce up to 46 times more false positives. False-negative test results can also influence patient treatment and outcomes. The probability of a false-negative test for LD with a single test for early-stage disease was high at 66.8%, increasing to 74.9% for two-tier testing. With the least sensitive HIV test used in the two-stage test, the false-negative rate was 1.3%, indicating that the LD test generates ~60 times as many false-negative results. For late-stage LD, the two-tier test generated 16.7% false negatives compared with 0.095% false negatives generated by a two-step HIV test, which is over a 170-fold difference. Using clinically representative LD test sensitivities, the two-tier test generated over 500 times more false-negative results than two-stage HIV testing.

Bone turnover predicts change in volumetric bone density and bone geometry at the radius in men

Peripheral quantitative computed tomography scans of the distal and midshaft radius were performed in 514 European men aged 40-79 years at baseline and a median of 4.3 years later. Age-related changes in volumetric bone mineral density (vBMD) and bone geometry were greater in men with higher biochemical markers of bone turnover at baseline.

INTRODUCTION

This study aimed to determine prospective change in bone density and geometry at the radius in men and examine the influence of bone turnover markers and sex hormones on that change.

METHODS

Men aged 40-79 years were recruited from population registers in Manchester (UK) and Leuven (Belgium). At baseline, markers of bone formation (P1NP and osteocalcin) and resorption (β-cTX and ICTP) were assessed. Total and bioavailable testosterone and oestradiol were also measured. Peripheral quantitative computed tomography (pQCT) was used to scan the radius at distal and midshaft sites at the baseline assessment and a median of 4.3 years later.

RESULTS

Five hundred fourteen men, mean (SD) age of 59.6 (10.5) years, contributed to the data. At the midshaft site, there was a significant decrease in mean cortical vBMD (-0.04 %/year), bone mineral content (BMC) (-0.1 %/year) and cortical thickness (-0.4 %/year), while total and medullary area increased (+0.5 and +2.4 %/year respectively). At the distal radius, total vBMD declined (-0.5 %/year) and radial area increased (+0.6 %/year). Greater plasma concentrations of bone resorption and formation markers were associated with greater decline in BMC and cortical area at the midshaft and total vBMD at the distal site. Increased bone resorption was linked with an increase in total and medullary area and decrease in cortical thickness at the midshaft. Sex hormone levels were unrelated to change in pQCT parameters.

CONCLUSIONS

Age-related changes in vBMD and bone geometry are greater in men with higher biochemical markers of bone turnover at baseline. Sex hormones have little influence on change in pQCT parameters.

Commercial test kits for detection of Lyme borreliosis: a meta-analysis of test accuracy

The clinical diagnosis of Lyme borreliosis can be supported by various test methodologies; test kits are available from many manufacturers. Literature searches were carried out to identify studies that reported characteristics of the test kits. Of 50 searched studies, 18 were included where the tests were commercially available and samples were proven to be positive using serology testing, evidence of an erythema migrans rash, and/or culture. Additional requirements were a test specificity of ≥85% and publication in the last 20 years. The weighted mean sensitivity for all tests and for all samples was 59.5%. Individual study means varied from 30.6% to 86.2%. Sensitivity for each test technology varied from 62.4% for Western blot kits, and 62.3% for enzyme-linked immunosorbent assay tests, to 53.9% for synthetic C6 peptide ELISA tests and 53.7% when the two-tier methodology was used. Test sensitivity increased as dissemination of the pathogen affected different organs; however, the absence of data on the time from infection to serological testing and the lack of standard definitions for “early” and “late” disease prevented analysis of test sensitivity versus time of infection. The lack of standardization of the definitions of disease stage and the possibility of retrospective selection bias prevented clear evaluation of test sensitivity by “stage”. The sensitivity for samples classified as acute disease was 35.4%, with a corresponding sensitivity of 64.5% for samples from patients defined as convalescent. Regression analysis demonstrated an improvement of 4% in test sensitivity over the 20-year study period. The studies did not provide data to indicate the sensitivity of tests used in a clinical setting since the effect of recent use of antibiotics or steroids or other factors affecting antibody response was not factored in. The tests were developed for only specific Borrelia species; sensitivities for other species could not be calculated.

Lower bone turnover and relative bone deficits in men with metabolic syndrome: a matter of insulin sensitivity? The European Male Ageing Study

We examined cross-sectional associations of metabolic syndrome and its components with male bone turnover, density and structure. Greater bone mass in men with metabolic syndrome was related to their greater body mass, whereas hyperglycaemia, hypertriglyceridaemia or impaired insulin sensitivity were associated with lower bone turnover and relative bone mass deficits.

INTRODUCTION

Metabolic syndrome (MetS) has been associated with lower bone turnover and relative bone mass or strength deficits (i.e. not proportionate to body mass index, BMI), but the relative contributions of MetS components related to insulin sensitivity or obesity to male bone health remain unclear.

METHODS

We determined cross-sectional associations of MetS, its components and insulin sensitivity (by homeostatic model assessment-insulin sensitivity (HOMA-S)) using linear regression models adjusted for age, centre, smoking, alcohol, and BMI. Bone turnover markers and heel broadband ultrasound attenuation (BUA) were measured in 3129 men aged 40-79. Two centres measured total hip, femoral neck, and lumbar spine areal bone mineral density (_aBMD, n = 527) and performed radius peripheral quantitative computed tomography (pQCT, n = 595).

RESULTS

MetS was present in 975 men (31.2 %). Men with MetS had lower β C-terminal cross-linked telopeptide (β-CTX), N-terminal propeptide of type I procollagen (PINP) and osteocalcin (P < 0.0001) and higher total hip, femoral neck, and lumbar spine _aBMD (P ≤ 0.03). Among MetS components, only hypertriglyceridaemia and hyperglycaemia were independently associated with PINP and β-CTX. Hyperglycaemia was negatively associated with BUA, hypertriglyceridaemia with hip _aBMD and radius cross-sectional area (CSA) and stress-strain index. HOMA-S was similarly associated with PINP and β-CTX, BUA, and radius CSA in BMI-adjusted models.

CONCLUSIONS

Men with MetS have higher _aBMD in association with their greater body mass, while their lower bone turnover and relative deficits in heel BUA and radius CSA are mainly related to correlates of insulin sensitivity. Our findings support the hypothesis that underlying metabolic complications may be involved in the bone's failure to adapt to increasing bodily loads in men with MetS.

Ethnic differences in bone geometry between White, Black and South Asian men in the UK

Relatively little is known about the bone health of ethnic groups within the UK and data are largely restricted to women. The aim of this study was to investigate ethnic differences in areal bone mineral density (aBMD), volumetric bone mineral density (vBMD), bone geometry and strength in UK men. White European, Black Afro-Caribbean and South Asian men aged over 40years were recruited from Greater Manchester, UK. aBMD at the spine, hip, femoral neck and whole body were measured by DXA. Bone geometry, strength and vBMD were measured at the radius and tibia using pQCT at the metaphysis (4%) and diaphysis (50% radius; 38% tibia) sites. Adjustments were made for age, weight and height. Black men had higher aBMD at the whole body, total hip and femoral neck compared to White and South Asian men independent of body size adjustments, with no differences between the latter two groups. White men had longer hip axis lengths than both Black and South Asian men. There were fewer differences in vBMD but White men had significantly lower cortical vBMD at the tibial diaphysis than Black and South Asian men (p<0.001). At the tibia and radius diaphysis, Black men had larger bones with thicker cortices and greater bending strength than the other groups. There were fewer differences between White and South Asian men. At the metaphysis, South Asian men had smaller bones (p=0.02) and lower trabecular vBMD at the tibia (p=0.003). At the diaphysis, after size-correction, South Asian men had similar sized bones but thinner cortices than White men; measures of strength were not broadly reduced in the South Asian men. Combining pQCT and DXA measurements has given insight into differences in bone phenotype in men from different ethnic backgrounds. Understanding such differences is important in understanding the aetiology of male osteoporosis.

Predictors and outcomes of sustained, intermittent or never achieving remission in patients with recent onset inflammatory polyarthritis: results from the Norfolk Arthritis Register

OBJECTIVES

Early remission is the current treatment strategy for patients with inflammatory polyarthritis (IP) and RA. Our objective was to identify baseline factors associated with achieving remission: sustained (SR), intermittent (IR) or never (NR) over a 5-year period in patients with early IP.

METHODS

Clinical and demographic data of patients with IP recruited to the Norfolk Arthritis Register (NOAR) were obtained at baseline and years 1, 2, 3 and 5. Remission was defined as no tender or swollen joints (out of 51). Patients were classified as NR or PR, respectively, if they were in remission at: no assessment or ⩾3 consecutive assessments after baseline, and IR otherwise. Ordinal regression and a random effects model, respectively, were used to examine the association between baseline factors, remission group and HAQ scores over time.

RESULTS

A total of 868 patients (66% female) were included. Of these, 54%, 34% and 12% achieved NR, IR and SR, respectively. In multivariate analysis, female sex (odds ratio, OR 0.47, 95% CI: 0.35, 0.63), higher tender joint count (OR = 0.94, 95% CI: 0.93, 0.96), higher HAQ (OR = 0.59, 95% CI: 0.48, 0.74), being obese (OR = 0.70, 95% CI: 0.50, 0.99), hypertensive (OR = 0.67, 95% CI: 0.50, 0.90) or depressed (OR = 0.74, 95% CI: 0.55, 1.00) at baseline were independent predictors of being in a lower remission group. IR and SR were associated with lower HAQ scores over time and lower DAS28 at year 5.

CONCLUSION

Women with higher tender joint count and disability at baseline, depression, obesity and hypertension were less likely to achieve remission. This information could help when stratifying patients for more aggressive therapy.

Delivery of a hydrophobic phthalocyanine photosensitizer using PEGylated gold nanoparticle conjugates for the in vivo photodynamic therapy of amelanotic melanoma

Gold nanoparticles functionalised with PEG and a phthalocyanine photosensitiser achieved 40% no tumour regrowth and complete survival followingin vivoPDT.

Model-based estimation of intra-cortical connectivity using electrophysiological data

This paper provides a new method for model-based estimation of intra-cortical connectivity from electrophysiological measurements. A novel closed-form solution for the connectivity function of the Amari neural field equations is derived as a function of electrophysiological observations. The resultant intra-cortical connectivity estimate is driven from experimental data, but constrained by the mesoscopic neurodynamics that are encoded in the computational model. A demonstration is provided to show how the method can be used to image physiological mechanisms that govern cortical dynamics, which are normally hidden in clinical data from epilepsy patients. Accurate estimation performance is demonstrated using synthetic data. Following the computational testing, results from patient data are obtained that indicate a dominant increase in surround inhibition prior to seizure onset that subsides in the cases when the seizures spread.

Upgrade of MacCHESS facility for X-ray scattering of biological macromolecules in solution

X-ray scattering of biological macromolecules in solution is an increasingly popular tool for structural biology and benefits greatly from modern high-brightness synchrotron sources. The upgraded MacCHESS BioSAXS station is now located at the 49-pole wiggler beamline G1. The 20-fold improved flux over the previous beamline F2 provides higher sample throughput and autonomous X-ray scattering data collection using a unique SAXS/WAXS dual detectors configuration. This setup achieves a combined q-range from 0.007 to 0.7 Å(-1), enabling better characterization of smaller molecules, while opening opportunities for emerging wide-angle scattering methods. In addition, a facility upgrade of the positron storage ring to continuous top-up mode has improved beam stability and eliminated beam drift over the course of typical BioSAXS experiments. Single exposure times have been reduced to 2 s for 3.560 mg ml(-1) lysozyme with an average quality factor I/σ of 20 in the Guinier region. A novel disposable plastic sample cell design that incorporates lower background X-ray window material provides users with a more pristine sample environment than previously available. Systematic comparisons of common X-ray window materials bonded to the cell have also been extended to the wide-angle regime, offering new insight into best choices for various q-space ranges. In addition, a quantitative assessment of signal-to-noise levels has been performed on the station to allow users to estimate necessary exposure times for obtaining usable signals in the Guinier regime. Users also have access to a new BioSAXS sample preparation laboratory which houses essential wet-chemistry equipment and biophysical instrumentation. User experiments at the upgraded BioSAXS station have been on-going since commissioning of the beamline in Summer 2013. A planned upgrade of the G1 insertion device to an undulator for the Winter 2014 cycle is expected to further improve flux by an order of magnitude.

Cancer targeting with biomolecules: a comparative study of photodynamic therapy efficacy using antibody or lectin conjugated phthalocyanine-PEG gold nanoparticles

The functionalisation of therapeutic nanoparticle constructs with cancer-specific biomolecules can enable selective tumour accumulation and targeted treatment.

Lyme borreliosis: a review of data on transmission time after tick attachment

Lyme borreliosis is increasing rapidly in many parts of the world and is the most commonly occurring vector-borne disease in Europe and the USA. The disease is transmitted by ticks of the genus Ixodes. They require a blood meal at each stage of their life cycle and feed on a wide variety of wild and domestic animals as well as birds and reptiles. Transmission to humans is incidental and can occur during visits to a vector habitat, when host mammals and their associated ticks migrate into the urban environment, or when companion animals bring ticks into areas of human habitation. It is frequently stated that the risk of infection is very low if the tick is removed within 24–48 hours, with some claims that there is no risk if an attached tick is removed within 24 hours or 48 hours. A literature review has determined that in animal models, transmission can occur in <16 hours, and the minimum attachment time for transmission of infection has never been established. Mechanisms for early transmission of spirochetes have been proposed based on their presence in different organs of the tick. Studies have found systemic infection and the presence of spirochetes in the tick salivary glands prior to feeding, which could result in cases of rapid transmission. Also, there is evidence that spirochete transmission times and virulence depend upon the tick and Borrelia species. These factors support anecdotal evidence that Borrelia infection can occur in humans within a short time after tick attachment.

Liquid crystalline properties of unsymmetrically substituted phthalocyanines: structural features leading to nematic mesophase materials

A novel homologous series of four 1,4,8,11,15,18-hexakis(pentyl)-22-methyl-25-hydroxyalkylphthalocyanine derivatives with the hydroxyalkyl chain varying from hydroxynonyl through to hydroxydodecyl has been synthesized to investigate the role of the hydroxyalkyl chain in promoting thermotropic liquid crystalline behavior. Polarizing optical miscoscopy reveals that the compound with the shortest hydroxyalkyl chain (hydroxynonyl) exhibits a mesophase with a texture characteristic of a columnar mesophase, common among liquid crystalline phthalocyanine derivatives. However, as the chain is lengthened along the series, there appears a second type of mesophase that shows a schlieren texture. Such a texture is characteristic of a nematic phase and rare among liquid crystalline phthalocyanine derivatives. A fifth compound, the novel 1,4,8,11,15,18-hexakis(pentyl)-22-methyl-25-dodecylphthalocyanine, exhibits only columnar mesophase behavior suggesting that the hydroxyl group at the end of the longer chains of the former compounds is important in developing the nematic phase.

Combining cutaneous silent periods with quantitative sudomotor axon reflex testing in the assessment of diabetic small fiber neuropathy

OBJECTIVE

Routine electrophysiological testing is often normal in the evaluation of painful diabetic neuropathy, as it is unable to detect dysfunction of thinly myelinated (Aδ) and unmyelinated (C) small fibers. Although cutaneous silent periods (CSP) and quantitative sudomotor axon reflex testing (QSART) respectively evaluate these fiber types in the extremities, these two tests have yet to be assessed together.

METHODS

26 patients with a clinical diagnosis of small fiber neuropathy (SFN) and 26 age-matched controls were assessed. Nine patients had Type I diabetes, nine had Type II diabetes, and eight had impaired glucose tolerance. The CSP onset latency and duration were recorded in each extremity. QSART was performed on the right side.

RESULTS

58% (15/26) of patients had abnormal sweat volumes obtained from QSART, while 50% (13/26) of patients had abnormal CSP responses. Combining these two tests increased the sensitivity of testing to 77% (20/26). Abnormalities were seen equally across all patient groups.

CONCLUSIONS

Combining CSP with QSART significantly increases the sensitivity of testing when assessing patients with SFN related to diabetes, or prediabetes.

SIGNIFICANCE

For clinically suspected SFN, it is preferable to test more than one small fiber type, as each possess different structural and functional properties and may be heterogeneously affected between patients.

Octaoctyl-substituted lutetium bisphthalocyanine for NADH biosensing

Cyclic voltammetric and Raman and UV-vis spectroscopic measurements were performed on thin films of nonperipherally substituted bis[1,4,8,11,15,18,22,25-octakis(octyl)phthalocyaninato] lutetium(III) (R16LuPc2). Voltammograms exhibit one-electron quasi-reversible redox processes in 1.5 M LiClO4 aqueous solutions. The red-shift of the Q-band of R16LuPc2 in the UV-visible absorption spectra upon oxidation is attributed to the shortening of the inter-ring distance between the two phthalocyanine moieties. This observation is also consistent with the shift in the redox-sensitive vibrational modes in the Raman spectra due to the localization of the positive charge on phthalocyanine moieties. Neutralization of the oxidized R16LuPc2(+) film by dihydronicotinamide adenine dinucleotide (NADH) using different concentrations varying from 0.05 to 1 mM has been studied by UV-vis absorption and Raman spectroscopies. The reduction processes for a three month old film were found to be slower than those for freshly prepared films and showed a dependence upon NADH concentration. The data provide a basis for application of R16LuPc2 as a sensor for NADH.