The disproportionate impact of chronic arthralgia and arthritis among women

Technologies for Evaluation of Pelvic Floor Functionality: A Systematic Review

Pelvic floor dysfunction is a common problem in women and has a negative impact on their quality of life. The aim of this review was to provide a general overview of the current state of technology used to assess pelvic floor functionality. It also provides literature research of the physiological and anatomical factors that correlate with pelvic floor health. This systematic review was conducted according to the PRISMA guidelines. The PubMed, ScienceDirect, Cochrane Library, and IEEE databases were searched for publications on sensor technology for the assessment of pelvic floor functionality. Anatomical and physiological parameters were identified through a manual search. In the systematic review, 114 publications were included. Twelve different sensor technologies were identified. Information on the obtained parameters, sensor position, test activities, and subject characteristics was prepared in tabular form from each publication. A total of 16 anatomical and physiological parameters influencing pelvic floor health were identified in 17 published studies and ranked for their statistical significance. Taken together, this review could serve as a basis for the development of novel sensors which could allow for quantifiable prevention and diagnosis, as well as particularized documentation of rehabilitation processes related to pelvic floor dysfunctions.

Sex differences in dynamic joint stiffness during walking in older adults

BACKGROUND

Knee osteoarthritis (OA) often occurs in older women. Walking assistance such as knee brace is used to reduce mechanical stress on the knee, preventing OA onset. Dynamic joint stiffness (DJS) quantifies the resistance of an assistive device, providing a foundation for an objective bending stiffness prescription model. DJS may show sex differences among older adults.

RESEARCH QUESTION

This study aimed to investigate sex differences in lower limb DJS in the sagittal plane during walking in older adults.

METHODS

A total of 132 healthy older adults, aged 65 years or older (71 men and 61 women), were extracted from a public dataset. DJS of the hip, knee, and ankle joints in the sagittal plane was determined during the power absorption phase of the stance. DJS, joint angular excursion, and Δ joint moment were compared between older men and women using the Mann-Whitney U test. In addition, the r-value was calculated to represent the effect size of the differences in amplitude.

RESULTS

Ankle DJS in older women was significantly lower with a reduced Δ ankle plantar flexion moment compared with that into men (p < 0.001 and p = 0.001; r = 0.35 and 0.42, respectively). Additionally, knee DJS was lower in older women (p = 0.007). However, since the joint angular excursion and ΔMoment showed no differences (p = 0.624 and 0.222, respectively), the effect size was small (r = 0.24). Hip DJS showed no significant sex differences (p = 0.703).

SIGNIFICANCE

These results suggest that the decrease in ankle DJS in older women was caused by the reduced ankle plantarflexion moment. Thus, support for ankle DJS is necessary for healthy older women. Nonetheless, knee DJS does not elucidate the cause of knee OA in the older women.

L-shaped association between serum 25-hydroxyvitamin D and all-cause mortality of individuals with rheumatoid arthritis

OBJECTIVE

We aimed to examine the relationship between serum 25-hydroxyvitamin D and all-cause, cause-specific mortality of patients with RA.

METHODS

This cohort study included 1466 patients with RA from The National Health and Nutrition Examination Survey (NHANES) 2001-14. Mortality status was obtained according to death certificate records from the National Death Index. Cox proportional risk models were used to estimate hazard ratios (HR) and 95% CI for mortality. A generalized additive model, smooth curve fitting and 2-piecewise Cox proportional hazards models were established to address the nonlinearity between serum 25-hydroxyvitamin D and mortality.

RESULTS

A total of 1466 patients [mean (s.d.) 59.89 (14.14) years old; 58.94% female] were enrolled. The weighted mean level of 25-hydroxyvitamin D was 59.26 (24.99) nmol/l and 38.95% were found with deficient (or severe deficient) vitamin D (<50.00 nmol/l). During 10453 person-years of follow-up, 268 patients were documented for all-cause death, including 52 cardiovascular disease （CVD）deaths and 48 cancer deaths. Compared with patients with serum 25-hydroxyvitamin D <25.00 nmol/l, patients with higher serum 25-hydroxyvitamin D were more likely to have lower rate of all-cause mortality. Nonlinear and L-shaped association between serum 25-hydroxyvitamin D and all-cause mortality was found, and decreased serum 25-hydroxyvitamin D was significantly associated with increased risk of all-cause mortality in patients with serum 25-hydroxyvitamin D <37.30 nmol/l [HR 0.95 (0.92, 0.98); P < 0.01].

CONCLUSION

An L-shaped association between serum 25-hydroxyvitamin D and all-cause mortality was found among patients with RA, indicating that serum 25-hydroxyvitamin D should be improved to a certain level for the prevention of premature death.

Gait biomechanics phenotypes among total knee arthroplasty candidates by machine learning cluster analysis

Knee osteoarthritis patient phenotyping is relevant to developing targeted treatments and assessing the treatment efficacy of total knee arthroplasty (TKA). This study aimed to identify clusters among TKA candidates based on demographic and knee mechanic features during gait, and compare gait changes between clusters postoperatively. TKA patients underwent 3D gait analysis 1-week pre (n = 134) and 1-year post-TKA (n = 105). Principal component analysis was applied to frontal and sagittal knee angle and moment waveforms, extracting major patterns of variability. Age, sex, body mass index, gait speed, and frontal and sagittal pre-TKA angle and moment PC scores previously identified as relevant to TKA outcomes were standardized (mean = 0, SD = 1, [134 × 15]). Multidimensional scaling and machine learning-based hierarchical clustering were applied. Final clusters were validated by examining intercluster differences pre-TKA and gait feature changes (Post_PCscore  - Pre_PCscore ) by k-way Χ² and ANOVA tests. Four TKA candidate phenotypes yielded optimum clustering metrics, interpreted as higher and lower functioning clusters that were predominantly male and female. Higher functioning clusters pre-TKA (clusters 1 and 4) had more dynamic sagittal flexion moment (p < 0.001) and frontal plane adduction moment (p < 0.001) loading/un-loading patterns during stance. Post-TKA, higher functioning clusters demonstrated less knee mechanic improvements during gait (flexion angle p < 0.001; flexion moment p < 0.001). TKA candidates can be characterized by four clusters, predominately separated by sex and knee joint biomechanics. Post-TKA knee kinematics and kinetics improvements were cluster-specific; lower functioning clusters experienced more improvement. Cluster-based patient profiling may aid in triaging and developing OA management and surgical strategies meeting group-level function needs.

Acute effects of low load resistance training with blood flow restriction on serum growth hormone, insulin-like growth factor-1, and testosterone in patients with mild to moderate unilateral knee osteoarthritis

Objective

To investigate the acute effects of blood flow restriction (BFR) with single-leg low load resistance exercise and high load resistance exercise on serum insulin-like growth factor-1 (IGF-1), growth hormone (GH), and testosterone in patients with unilateral knee osteoarthritis (OA).

Methods

This study recruited 18 postmenopausal female patients with mild to moderate unilateral knee OA, which was then followed by randomly conducting three resistance exercise protocols by drawing lots: 1. A 30% 1-repetition maximum (1-RM) resistance exercise with BFR of 70% arterial occlusive pressure (AOP) (BFR group); 2. A 70% 1-RM resistance exercise without BFR (RES group); 3. A 30% 1-RM resistance exercise without BFR (CON group). Blood lactate (BLA) and muscle growth related hormone levels were tested at 4-time points: before exercise, immediately after exercise, 15 min after exercise, and 30 min after exercise.

Results

There was no statistical difference between the indexes in each group before exercise, but the different exercise had different effects on each index and also an interactive effect (P < 0.05). The increase of rating of perceived exertion in the BFR and RES groups, which were of similar magnitude, was greater compared to the levels in the CON group (P < 0.05). Post-exercise BLA levels were lower in the CON group in comparison to the BFR and RES groups (P < 0.05). Rather than the RES group, GH levels of the BFR group were also significantly higher than the CON group (P < 0.05) at 15 min post-exercise. At post- and 15 min after exercise, the CON group recorded significantly lower IGF-1 levels compared to the BFR and RES groups (P < 0.05). At post- and 15 min after exercise, the CON group (P < 0.05) reflected the lowest testosterone levels, followed by the RES group (P < 0.05), and the highest in the BFR group (P < 0.05).

Conclusions

Myogenesis-related hormones in women with unilateral knee OA could be increased by high load resistance exercise and low load resistance exercise with BFR on unaffected limb.

Relationship Between the Choice of Clinical Treatment, Gait Functionality and Kinetics in Patients With Comparable Knee Osteoarthritis

Objective: The objective of this study was to investigate the relationship between the choice of clinical treatment, gait functionality, and kinetics in patients with comparable knee osteoarthritis.

Design: This was an observational case-control study.

Setting: The study was conducted in a university biomechanics laboratory.

Participants: Knee osteoarthritis patients were stratified into the following groups: clinical treatment (conservative/total knee replacement (TKR) planned), sex (male/female), age (60–67/68–75), and body mass index (BMI) (&lt;30/≥30). All patients had a Kellgren–Lawrence score of 2 or 3 (N = 87).

Main Outcome Measures: All patients underwent gait analysis, and two groups of dependent variables were extracted:

• Spatiotemporal gait variables: gait velocity, stride time, and double-support time, which are associated with patient functionality.

• Kinetic gait variables: vertical, anterior–posterior, and mediolateral ground reaction forces, vertical free moment, joint forces, and moments at the ankle, knee, and hip. Multifactorial and multivariate analyses of variance were performed.

Results: Functionality relates to treatment decisions, with patients in the conservative group walking 25% faster and spending 24% less time in the double-support phase. However, these differences vary with age and are reduced in older subjects. Patients who planned to undergo TKR did not present higher knee forces, and different joint moments between clinical treatments depended on the age and BMI of the subjects.

Conclusions: Knee osteoarthritis is a multifactorial disease, with age and BMI being confounding factors. The differences in gait between the two groups were mitigated by confounding factors and risk factors, such as being a woman, elderly, and obese, reducing the variability of the gait compression loads. These factors should always be considered in gait studies of patients with knee osteoarthritis to control for confounding effects.

Age and sex differences in normative gait patterns

BACKGROUND

A comprehensive understanding of healthy gait patterns is a critical first step towards understanding age-related pathologies and disorders that are commonly associated with mobility limitations throughout aging. Further, consideration of sex-specific gait patterns throughout the lifespan is important, considering biological differences between males and females that can manifest biomechanically, and epidemiological evidence of female sex being a risk factor for some age-related pathologies such as osteoarthritis.

RESEARCH QUESTION

The aim of this study was to characterize the differences in lower extremity joint kinematics and kinetics during gait between asymptomatic adult women and men in different age groups (20-40 years, 41-50 years, 51-59 years, 60+ years).

METHODS

This was a secondary analysis conducted on instrumented gait data from 154 asymptomatic adult participants (94 females, 60 males). Three-dimensional hip, knee and ankle joint angles and net external moments were calculated and waveform principal component analysis (PCA) was applied to extract major patterns of variability from each. PC scores were examined for significant sex, age and interaction effects using a two-factor ANOVA analysis (p = 0.001).

RESULTS

13 PC features differed between asymptomatic male and female gait patterns, and were independent of age category. No PC features significantly differed between the age groups, and there were no significant sex by age interactions.

SIGNIFICANCE

There are significant magnitude and pattern differences in hip, knee and ankle kinematics and kinetics between asymptomatic women and men. As study participants were asymptomatic, these differences do not necessarily correlate with any injury or disease mechanisms. However, these results do suggest the importance of considering sex-specific analyses in gait study design, and the use of sex-specific normative data in clinical gait studies. These results further suggest that consideration of strict age-matching for gait analysis studies using adult controls is not as critical as sex considerations.

Anti-inflammatory Diet In Rheumatoid Arthritis (ADIRA)-a randomized, controlled crossover trial indicating effects on disease activity

BACKGROUND

Many patients with rheumatoid arthritis (RA) report symptom relief from certain foods. Earlier research indicates positive effects of food and food components on clinical outcomes in RA, but insufficient evidence exists to provide specific dietary advice. Food components may interact but studies evaluating combined effects are lacking.

OBJECTIVES

We aimed to investigate if an anti-inflammatory diet reduces disease activity in patients with RA.

METHODS

In this single-blinded crossover trial, 50 patients with RA were randomly assigned to an intervention diet containing a portfolio of suggested anti-inflammatory foods, or a control diet similar to the general dietary intake in Sweden, for 10 wk. After a 4-mo washout period the participants switched diet. Food equivalent to ∼50% of energy requirements was delivered weekly to their homes. For the remaining meals, they were encouraged to consume the same type of foods as the ones provided during each diet. Primary outcome was change in Disease Activity Score in 28 joints-Erythrocyte Sedimentation Rate (DAS28-ESR). Secondary outcomes were changes in the components of DAS28-ESR (tender and swollen joints, ESR, and visual analog scale for general health) and DAS28-C-reactive protein.

RESULTS

In the main analysis, a linear mixed ANCOVA model including the 47 participants completing ≥1 diet period, there was no significant difference in DAS28-ESR between the intervention and control periods (P = 0.116). However, in unadjusted analyses, DAS28-ESR significantly decreased during the intervention period and was significantly lower after the intervention than after the control period in the participants who completed both periods (n = 44; median: 3.05; IQR: 2.41, 3.79 compared with median: 3.27; IQR: 2.69, 4.28; P = 0.04, Wilcoxon's Signed Rank test). No significant differences in the components were observed.

CONCLUSIONS

This trial indicates positive effects of a proposed anti-inflammatory diet on disease activity in patients with RA. Additional studies are required to determine if this diet can cause clinically relevant improvements.This trial was registered at clinicaltrials.gov as NCT02941055.

Sex Differences in Quality of Life and Health Services Utilization among Elderly People in Rural Vietnam

As in much of the world, the elderly population in Vietnam is growing rapidly with two-thirds of them currently living in rural areas. Besides limited access to quality healthcare services, they also have unique health profiles and needs due to various factors, including the highly skewed sex ratio of more women residing in rural areas. However, the relationship between gender, health-seeking behaviors, and health outcomes in this under-served population has not been well characterized. This study sought to explore the associations of gender with health-related quality of life and health-seeking behavior among the elderly in Soc Son, a rural district of Hanoi, Vietnam. A cross-sectional design was used; elderly individuals were surveyed across the domains of socioeconomic information, health status, and healthcare service utilization. We found that overall, women had poorer health and quality of life even though gender difference did not appear to significantly influence their levels of health services utilization. A greater understanding of the systemic, sociocultural, and psychological factors underlying such differences may help better inform future healthcare service delivery strategies targeting this growing population in rural areas.

Association between the aspartic acid D-repeat polymorphisms and osteoarthritis susceptibility: An updated systematic review and meta-analyses

OBJECTIVES

Association between the D-repeat of asporin (ASPN) gene and osteoarthritis (OA) was still inconsistent. We performed this meta-analysis to systematically assess the D-repeat polymorphisms in OA susceptibility.

METHODS

Relevant studies were enrolled by searching databases. Odd ratios (ORs) with 95% confidence intervals (95% CIs) were used for evaluating the association between ASPN gene and OA. Heterogeneity was calculated using the Q statistic, and three different subgroup analyses were performed on ethnicity, gender, and OA positions respectively. False discovery rate (FDR) was applied to regulate the multiple comparisons.

RESULTS

Twelve qualified articles involving 5190 OA patients and 5167 healthy controls were included. With D13 polymorphism, Caucasian male patients have low OA susceptibility (P = .008, PFDR = .024, OR [95% CI] = 0.83 [0.73-0.95]). As to D14 polymorphism, all male patients (P = .0004, PFDR = .001, OR [95% CI] = 1.38 [1.15-1.64]), Asian male patients (P = .01, PFDR = .01, OR [95% CI] = 1.72 [1.11-2.66]), and Caucasian male patients (P = .005, PFDR = .001, OR [95% CI] = 1.32 [1.09-1.60]) have high OA susceptibility. In the pooled-population of KOA with D14 polymorphism, overall male patients (P = .03, PFDR = .045, OR [95% CI] = 1.35 [1.02-1.78]) and Asian male patients (P = .01, PFDR = .03, OR [95% CI] = 1.72 [1.11-2.66]) have high OA risk. With D16 polymorphism, Latin America patients may have high OA risk (P = .04, PFDR = .15, OR [95% CI] = 1.43 [1.02-2.01]).

CONCLUSION

Our results suggest that D-repeat of ASPN gene is mainly associated with male patients. The D13 polymorphism plays a protective role for OA in Caucasians male individuals while D14 plays a risk factor for KOA in male patients.

Quantifying walking ability in Japanese patients with knee osteoarthritis: Standard values derived from a multicenter study

BACKGROUND

We aimed to determine useful parameters for quantifying walking ability in patients with knee osteoarthritis.

METHODS

This study included 621 Japanese patients with knee osteoarthritis scheduled to undergo total knee arthroplasty at any of 14 participating hospitals. Sex, age, body mass index, osteoarthritis severity (Kellgren-Lawrence grade), laterality, prior contralateral surgery, and pain were analyzed for their influence on walking ability, which was evaluated in terms of the 5-m walk test and the Timed Up and Go test outcomes during preoperative hospitalization. Patients were stratified based on dichotomized values of the independent influencing factors of walking ability, and the standard values for parameters describing walking ability were obtained.

RESULTS

Multiple regression analysis revealed that sex, age, and Kellgren-Lawrence grade were factors influencing walking ability (5-m walk test and Timed Up and Go test outcomes). Therefore, the patients were stratified by sex, age, and Kellgren-Lawrence grade. The standard values (median values) for walking time on the 5-m walk test among patients aged 60-74/75-89 years were: 3.90/4.64 vs. 4.27/5.12 s for men vs. women with Kellgren-Lawrence grade III; 4.26/5.60 vs. 4.80/6.05 s for men vs. women with Kellgren-Lawrence grade IV. Regarding walking speed on the 5-m test, the standard values were: 1.28/1.08 vs. 1.17/0.98 m/s for men vs. women with Kellgren-Lawrence grade III; 1.17/0.89 vs. 1.04/0.83 m/s for men vs. women with Kellgren-Lawrence grade IV. Finally, the standard values for time on the Timed Up and Go test were: 8.52/10.30 vs. 9.30/11.74 s for men vs. women with Kellgren-Lawrence grade III; 9.40/12.90 vs. 10.05/13.20 s for men vs. women with Kellgren-Lawrence grade IV.

CONCLUSIONS

The standard values reported in this study can be used to quantify walking ability decline in patients with knee osteoarthritis and to aid in the decision to consider total knee arthroplasty.

Well-Being and Arthritis Incidence: The Role of Inflammatory Mechanisms. Findings From the English Longitudinal Study of Ageing

OBJECTIVE

Higher levels of well-being are associated with lower levels of inflammatory markers in healthy populations; however, it is unclear whether this association translates into a reduced risk of disease. In the current study, we tested whether the association between well-being and inflammation results in a lower risk of arthritis.

METHODS

The sample consisted of 5266 participants 50 years or older from the English Longitudinal Study of Ageing and included six waves of data collection. We used a structural equation modeling approach to test whether inflammatory markers (C-reactive protein [CRP] or fibrinogen) mediated the association between well-being and arthritis risk for a 10-year follow-up period.

RESULTS

Higher levels of well-being were associated with a decrease in arthritis risk (hazard ratio = 0.97 per unit, 95% confidence interval = 0.96 to 0.98, p < .001). Of the two inflammatory markers, only CRP was associated with arthritis risk. Mediation analysis revealed that the indirect effect of well-being (at wave 1) on arthritis risk via CRP (at wave 2) was significant (hazard ratio = 0.996, 95% confidence interval = 0.995 to 0.998, p < .001). This effect remained significant after adjustment for demographic and health behavior variables and depressive symptoms.

CONCLUSIONS

CRP accounts for a small proportion of the association between well-being and a reduced risk of arthritis.

Bioprinting of osteochondral tissues: A perspective on current gaps and future trends

Osteochondral tissue regeneration has remained a critical challenge in orthopaedic surgery, especially due to complications of arthritic degeneration arising out of mechanical dislocations of joints. The common gold standard of autografting has several limitations in presenting tissue engineering strategies to solve the unmet clinical need. However, due to the complexity of joint anatomy, and tissue heterogeneity at the interface, the conventional tissue engineering strategies have certain limitations. The advent of bioprinting has now provided new opportunities for osteochondral tissue engineering. Bioprinting can uniquely mimic the heterogeneous cellular composition and anisotropic extra-cellular matrix (ECM) organization, while allowing for targeted gene delivery to achieve heterotypic differentiation. In this perspective, we discuss the current advances made towards bioprinting of composite osteochondral tissues and present an account of challenges-in terms of tissue integration, long-term survival, and mechanical strength at the time of implantation-required to be addressed for effective clinical translation of bioprinted tissues. Finally, we highlight some of the future trends related to osteochondral bioprinting with the hope of in-clinical translation.

An Evaluation of the Calce Method for Age Estimation

The Calce method of skeletal age estimation (Am J Phys Anthropol, 148, 2012 and 11) uses the acetabular surface of the os coxa and was developed using 90 individuals from the J.C.B. Grant Skeletal collection. From this collection, pilot tests using a combined sample size of 55 randomized individuals yielded an accuracy of 54.5%. To eliminate the possible issue of variation within the collection, 30 individuals from those that Calce specifically used were assessed by two analysts. Accuracies of 53.3% and 56.7% were obtained, compared with Calce's reported accuracy of 81% (Am J Phys Anthropol, 148, 2012 and 11). This study also used 30 Japanese individuals from the Nagasaki University modern cadaver collection. Due to the high interobserver error (43.3%) and the low accuracies achieved (40% and 46.7%), the Calce method does not perform well on Japanese samples. The low accuracy of this method in general suggests that the trait descriptions should be refined to assist analysts in properly utilizing the method.

Wellbeing and Arthritis Incidence: the Survey of Health, Ageing and Retirement in Europe

BACKGROUND

A number of studies provide evidence for an association between psychosocial factors and risk of incident arthritis. Current evidence is largely limited to the examination of negative factors such as perceived stress, but positive factors such as subjective wellbeing may also play a role.

PURPOSE

The purpose of the current study was to investigate whether people with higher subjective wellbeing have a lower risk of developing arthritis.

METHODS

We used Cox proportional hazards regression to examine the prospective relationship between wellbeing (measured using the CASP-12) and incidence of arthritis over a 9-year period. The sample consisted of 13,594 participants aged ≥50 years from the Survey of Health, Ageing and Retirement in Europe.

RESULTS

There was a significant association between greater wellbeing and reduced incident arthritis that was stronger at younger ages. In sex-adjusted analyses, for a standard deviation increase in CASP-12 score, the hazard ratios (95 % confidence intervals) for incident arthritis in people aged <65 and ≥65 years were 0.73 (0.69-0.77) and 0.80 (0.77-0.85), respectively. After further adjustment for other established risk factors, these associations were attenuated but remained significant in both age groups: the fully adjusted hazard ratios were 0.82 (0.77-0.87) and 0.88 (0.82-0.95), respectively.

CONCLUSIONS

These results provide evidence for an association between greater wellbeing and reduced risk of incident arthritis and, more generally, support the theory that psychosocial factors are implicated in the aetiology of this disease. Future research needs to delineate the mechanisms underlying the association between wellbeing and arthritis risk.

Gender differences in gait kinematics for patients with knee osteoarthritis

BACKGROUND

Females have a two-fold risk of developing knee osteoarthritis (OA) as compared to their male counterparts and atypical walking gait biomechanics are also considered a factor in the aetiology of knee OA. However, few studies have investigated sex-related differences in walking mechanics for patients with knee OA and of those, conflicting results have been reported. Therefore, this study was designed to examine the differences in gait kinematics (1) between male and female subjects with and without knee OA and (2) between healthy gender-matched subjects as compared with their OA counterparts.

METHODS

One hundred subjects with knee OA (45 males and 55 females) and 43 healthy subjects (18 males and 25 females) participated in this study. Three-dimensional kinematic data were collected during treadmill-walking and analysed using (1) a traditional approach based on discrete variables and (2) a machine learning approach based on principal component analysis (PCA) and support vector machine (SVM) using waveform data.

RESULTS

OA and healthy females exhibited significantly greater knee abduction and hip adduction angles compared to their male counterparts. No significant differences were found in any discrete gait kinematic variable between OA and healthy subjects in either the male or female group. Using PCA and SVM approaches, classification accuracies of 98-100% were found between gender groups as well as between OA groups.

CONCLUSIONS

These results suggest that care should be taken to account for gender when investigating the biomechanical aetiology of knee OA and that gender-specific analysis and rehabilitation protocols should be developed.

"Just get on with it": qualitative insights of coming to terms with a deteriorating body for older women with osteoarthritis

Objective

To qualify the psychosocial burden of osteoarthritis for older women and identify factors perceived to assist with psychological adjustment to the disease.

Methods

Women who indicated being diagnosed/treated for osteoarthritis in the previous three years in the fifth survey of the Australian Longitudinal Study on Women’s Health provided the sampling frame. Participants were randomly sampled until saturation was reached using a systematic process. Thematic content analysis was applied to the 19 semi-structured telephone interviews using a realist framework.

Results

The findings indicate that the emotional burden of osteoarthritis is considerable, and the process of psychological adjustment complex. Older women with osteoarthritis have psychological difficulties associated with increasing pain and functional impairment. Psychological adjustment over time was attributed primarily to cognitive and attitudinal factors (e.g. stoicism, making downward comparisons and possessing specific notions about the cause of arthritis). This was a dynamic ‘day to day’ process involving a constant struggle between grieving physical losses and increasing dependence amidst symptom management.

Conclusion

The findings of this study add to the current understanding of the complex processes involved in psychological adjustment over time. Targeted interventions focused on assisting women with arthritis redefine self-concepts outside the confines of caring responsibilities, coupled with public health education programs around understanding the destructive nature of arthritis are required. Understanding the destructive and (potentially) preventable nature of arthritis may facilitate early detection and increased uptake of appropriate treatment options for osteoarthritis that have the ability to modify disease trajectories.

Knee joint biomechanics and neuromuscular control during gait before and after total knee arthroplasty are sex-specific

The future of total knee arthroplasty (TKA) surgery will involve planning that incorporates more patient-specific characteristics. Despite known biological, morphological, and functional differences between men and women, there has been little investigation into knee joint biomechanical and neuromuscular differences between men and women with osteoarthritis, and none that have examined sex-specific biomechanical and neuromuscular responses to TKA surgery. The objective of this study was to examine sex-associated differences in knee kinematics, kinetics and neuromuscular patterns during gait before and after TKA. Fifty-two patients with end-stage knee OA (28 women, 24 men) underwent gait and neuromuscular analysis within the week prior to and one year after surgery. A number of sex-specific differences were identified which suggest a different manifestation of end-stage knee OA between the sexes.

The influence of perceived stress on the onset of arthritis in women: findings from the Australian Longitudinal Study on women's health

BACKGROUND

Psychosocial factors are considered as risk factors for some chronic diseases. A paucity of research exists surrounding the role of perceived stress in arthritis onset.

PURPOSE

Perceived stress as a risk factor for arthritis development was explored in an ageing cohort of Australian women.

METHODS

This study focused on 12,202 women from the 1946-1951 cohort who completed the Australian Longitudinal Study on Women's Health surveys in 2001, 2004 and 2007. Longitudinal associations were modelled, with and without a time lag.

RESULTS

Findings from the multivariate time lag modelling, excluding women with persistent joint pain, revealed that perceived stress predicted the onset of arthritis, with women experiencing minimal and moderate/high stress levels having a 1.7 and 2.4 times greater odds of developing arthritis 3 years later, respectively (p's < 0.001).

CONCLUSION

Chronically perceiving life as stressful is detrimental to future health. The findings provide support for perceived stress to be considered alongside other modifiable risk factors.

The relative importance of psychosocial factors in arthritis: findings from 10,509 Australian women

OBJECTIVE

To determine the relative importance of psychosocial factors in arthritis diagnosis in an ageing cohort of Australian women.

METHODS

This study focused on 10,509 women from the 1946-1951 cohort who responded to questions on arthritis in the fifth mailed population-based survey of the Australian Longitudinal Study on Women's Health conducted in 2007.

RESULTS

Arthritis was characterised by widespread psychosocial concerns, particularly relating to chronic stress and poor mental health. Univariate analyses revealed that in comparison to women without stress, women with moderate/high stress levels had a 2.5-fold increase in reporting arthritis. Experiencing ongoing negative interpersonal life events concerning illness of a family member/close friend and relationship difficulties was also associated with a 1.4-fold increase in the reporting of arthritis. Likewise, significantly reduced levels of optimism and perceived social support were noted (all associations p<.001). Psychiatric diagnosis was also associated with a two-fold increase in having arthritis (p<.001). Following adjustment for behavioural, demographic and health-related characteristics, anxiety was the only psychosocial factor associated with arthritis (OR=1.4, 95% CI=1.2, 1.7; p<.001).

CONCLUSION

This study examined, epidemiologically, the relative importance of psychosocial factors in arthritis in an ageing cohort of Australian women. The findings from this population-based study indicate that women with arthritis are more likely to report a range of psychosocial-related problems, particularly with regard to chronic stress perception and anxiety. Longitudinal analyses are required to examine the processes by which stress and psychosocial factors may contribute to arthritis risk and poor adaptation in terms of health-related quality of life.

Hippocampal nerve growth factor potentiated by 17β-estradiol and involved in allodynia of inflamed TMJ in rat

The hippocampus is believed to play an important role in sex-based differences of pain perception. Whether estrogen potentiates allodynia in the inflamed temporomandibular joint (TMJ) through affecting the expressions of pain-related genes in the hippocampus remains largely unknown. Because the nerve growth factor (NGF) is an important gene related to inflammatory pain, we tested whether hippocampal NGF may be involved in TMJ inflammatory pain. Here we showed that the rat hippocampal NGF was upregulated by TMJ inflammation induced by complete Freund adjuvant. NGF upregulation was further potentiated by estradiol in a dose-dependent manner. In contrast, NGF transcription in the amygdala, prefrontal cortex, and thalamus was not affected by TMJ inflammation and estradiol. An intrahippocampal injection of NGF antibody or NGF receptor inhibitor K252a (inhibitor for tropomyosin receptor kinase A, TrkA) reduced the allodynia of inflamed TMJ in proestrous rats. Our data suggest that the hippocampal NGF is involved in estradiol-sensitized allodynia of inflammatory TMJ pain.

PERSPECTIVE

We report that complete Freund adjuvant-induced temporomandibular joint (TMJ) inflammation upregulated hippocampal nerve growth factor (NGF) expression, and estradiol replacement potentiated this upregulation. These results propose that estradiol could modulate TMJ pain through the NGF signaling pathway in the hippocampus to exacerbate TMJ pain and offer a possible mechanism of sexual dimorphism of temporomandibular disorder pain.

Outcomes analysis of Internet-based CME initiatives for diagnosis and treatment of fibromyalgia patients: transition from education to physician behavior to patient health

A well designed outcomes research study was performed in which 20 primary care physicians were selected to participate. Each physician had more than 30 fibromyalgia patients in their practice. The study design consisted of four phases. In phase one, physicians undertook a self-assessment of their practice. Phase two of the study involved diagnosis and treatment of a virtual case vignette. The third phase consisted of analysis of the data from phase two and providing feedback from an expert rheumatologist, and the fourth phase was to complete patient report forms for five patients in their practice. The year-long study was completed by 12 physicians and resulted in data on 60 patients. The results of this study provide an insight into how physicians are diagnosing and treating patients with fibromyalgia. In this study, we transition from continuing medical education to physician behavior to patient outcomes.

Sex differences in neuropeptide content and release from rat dental pulp

INTRODUCTION

Studies to examine sex differences in response to pain have suggested that females exhibit lower threshold responses to painful stimuli and that threshold response varies greatly at different stages of the menstrual cycle. Additional studies suggest that sex differences may be caused by societal sex roles or differences in anxiety responses by men and women.

OBJECTIVE

The purpose of this study was to evaluate biologically evident sex differences in male and female rats chronically treated with a systemic algogen, the nerve growth factor (NGF), by measuring neuropeptides (calcitonin gene-related peptide) content and release from isolated dental pulp.

METHODS

Rats were injected subcutaneously every other day with either murine NGF (1 mg/kg) or vehicle for 7 or 13 days. Isolated incisor pulp tissue was evaluated from these male and female rats (n = 96). Capsaicin-evoked neurosecretion of CGRP and tissue content were measured using a previously validated radioimmunoassay.

RESULTS

Dental pulp from female rats at 7 days showed significantly increased capsaicin-evoked immunoreactive CGRP release (>50% increase) compared with tissue from male rats. After 13 days, this release was significantly increased only in NGF-treated female rats (3-fold increase) when compared with control females or both male groups. The CGRP content in tissue from both female groups was also significantly increased after 7 days of treatment (>3 fold), but after 13 days this content was only significantly increased in tissue from NGF-treated female rats (P = .0001).

CONCLUSIONS

These data suggest that sex differences affect the role of NGF in the modulation of inflammation through the regulation of peripheral neuropeptide release and content.

Articular step-off and risk of post-traumatic osteoarthritis. Evidence today

The goal of treatment in intra-articular fractures is to obtain anatomical restoration of the articular surface and stable internal fixation. Studies have attempted to specify how accurately an articular fracture needs to be reduced to minimise the chances of a poor clinical outcome. In this study, the current evidence with regard to articular step-offs and risk of post-traumatic osteoarthritis (POA) is evaluated. A literature review based on pre-specified criteria, revealed 36 articles for critical analysis related to intra-articular injuries of distal radius, acetabulum, distal femur and tibial plateau.In the distal radius, step-offs and gaps detected with precise measurement techniques have been correlated with a higher incidence of radiographic POA, but in the second 5 years after injury, a negative clinical impact of these radiographic changes has not been convincingly demonstrated. Restoring the superior weight-bearing dome of the acetabulum to its pre-injury morphology decreases POA and improves patient outcomes. Involvement of the posterior wall, however, seems to bean adverse prognostic sign. This effect may be independent of articular reduction. In the tibial plateau, articular incongruities appear to be well tolerated, and factors only partially related to articular reduction are more important in determining outcome than articular step-off alone;these include joint stability, retention of the meniscus, and coronal alignment. Based on observational approach and evaluation of the studies, factors other than just the extent of articular displacement affect the management of articular fractures. Different joints and even different areas of the same joint appear to have different tolerances for post-traumatic articular step-offs.

Conservative treatment modalities and outcomes for osteoarthritis: the concomitant pyramid of treatment

This article reviews current treatment algorithms for the conservative treatment of hip and knee osteoarthritis. The available treatment options for osteoarthritis (physical therapy, medical therapeutics, steroid injections, nutraceuticals, hyaluronic acid injections, acupuncture, pulsed electrical stimulation, and topical ointments) are compared to determine efficacy in the treatment of pain and return of function in the osteoarthritic joint. A literature review was conducted to determine combinations of appropriate concomitant therapy. Based on the available literature, we conclude that an early transition to multimodal and concomitant therapy is the most efficacious approach to decrease pain and improve joint function in the osteoarthritic hip and knee.

A multivariate statistical ranking of clinical and gait measures before and after total knee replacement

The purpose of this study was to assess the use of a multivariate statistical method to rank clinical and gait variables, thus describing a ranking of patient dysfunction prior to and following total knee replacement (TKR) surgery. Twenty end-stage knee osteoarthritis (KOA) subjects scheduled for TKR and 20 healthy controls performed level walking and stair ascent twice: pre- (P1) and 6 months post-surgery (P2). Clinical and gait measures were entered into a principle component analysis (PCA) to determine orthogonal principle components (PCs). The PCs were entered into a discriminant function analysis to determine the best predictors of group membership. The PCA extracted three PCs for both the P1 and P2 data sets. Three orthogonal dimensions were formed: "knee dysfunction", "gait dysfunction", and "stair ascent dysfunction". For P1 the "knee dysfunction" dimension composed of both subjective and objective measures, best discriminated between end-stage knee osteoarthritis patients and controls. For P2, the "stair ascent dysfunction" dimension best discriminated between 6 months post-TKR patients and controls. The results of this study suggest that a multivariate statistical method provides a clinically relevant ranking of patient dysfunction prior to and following TKR. This ranking of dysfunction could serve to identify rehabilitation priorities.

Aspartic acid repeat polymorphism of the asporin gene with susceptibility to osteoarthritis of the knee in a Korean population

Osteoarthritis (OA) is a common disease that is characterized by the degeneration of joint cartilage in the knee, hip and hand. Recently, it has been reported that susceptibility to OA is affected by the number of aspartic acid (D) residues in the amino-terminal of the asporin protein. In order to investigate whether the association found in Japanese OA is also present in the Korean population, the frequency of the polymorphism was examined in 190 OA patients and 376 healthy controls. The D-repeat microsatellite polymorphism was examined by amplifying the asporin gene and sequencing its products. The frequencies of the D13 and D14 alleles were 69.7% (265/380) and 5.8% (22/380), respectively, in OA patients and 64.2% (483/752) and 8.7% (65/752), respectively, in healthy controls. When we adjusted for gender and age, there was no statistically significant difference between Korean OA patients and healthy controls (P=0.1082) in the allele frequency of D13 compared to the other alleles. However, a significant difference between female OA patients and their controls (P=0.0245) in the allele frequency of the D13 allele was found compared to the other alleles. There was no significant difference between Korean OA patients and healthy controls in the frequency of the D14 and other alleles (P=0.2339). These results suggest that asporin may play a role in OA susceptibility of the knee in the Korean female population.

Gender differences in skin: a review of the literature

BACKGROUND

There has been increasing interest in studying gender differences in skin to learn more about disease pathogenesis and to discover more effective treatments. Recent advances have been made in our understanding of these differences in skin histology, physiology, and immunology, and they have implications for diseases such as acne, eczema, alopecia, skin cancer, wound healing, and rheumatologic diseases with skin manifestations.

OBJECTIVE

This article reviews advances in our understanding of gender differences in skin.

METHODS

Using the PubMed database, broad searches for topics, with search terms such as gender differences in skin and sex differences in skin, as well as targeted searches for gender differences in specific dermatologic diseases, such as gender differences in melanoma, were performed. Additional articles were identified from cited references. Articles reporting gender differences in the following areas were reviewed: acne, skin cancer, wound healing, immunology, hair/alopecia, histology and skin physiology, disease-specific gender differences, and psychological responses to disease burden.

RESULTS

A recurring theme encountered in many of the articles reviewed referred to a delicate balance between normal and pathogenic conditions. This theme is highlighted by the complex interplay between estrogens and androgens in men and women, and how changes and adaptations with aging affect the disease process. Sex steroids modulate epidermal and dermal thickness as well as immune system function, and changes in these hormonal levels with aging and/or disease processes alter skin surface pH, quality of wound healing, and propensity to develop autoimmune disease, thereby significantly influencing potential for infection and other disease states. Gender differences in alopecia, acne, and skin cancers also distinguish hormonal interactions as a major target for which more research is needed to translate current findings to clinically significant diagnostic and therapeutic applications.

CONCLUSIONS

The published findings on gender differences in skin yielded many advances in our understanding of cancer, immunology, psychology, skin histology, and specific dermatologic diseases. These advances will enable us to learn more about disease pathogenesis, with the goal of offering better treatments. Although gender differences can help us to individually tailor clinical management of disease processes, it is important to remember that a patient's sex should not radically alter diagnostic or therapeutic efforts until clinically significant differences between males and females arise from these findings. Because many of the results reviewed did not originate from randomized controlled clinical trials, it is difficult to generalize the data to the general population. However, the pressing need for additional research in these areas becomes exceedingly clear, and there is already a strong foundation on which to base future investigations.

Gender differences in pharmacological response

Female sex has been shown to be a risk factor for clinically relevant adverse drug reactions. Is the increased risk due to sex differences in pharmacokinetics, in pharmacodynamics, or did females receive more medications and higher mg/kg doses than males? Recent studies suggest that all of the above may play a role. Generally, males weigh more than females, yet few drugs are dosed based on body weight. Drug concentrations are dependent on the volume of distribution (Vd) and clearance (Cl). Both parameters are dependent on body weight for most drugs independent of sex differences. Females have a higher percent body fat than males which can affect the Vd of certain drugs. Renal clearance of unchanged drug is decreased in females due to a lower glomerular filtration. Sex differences in activity of the cytochrome P450 (CYP) and uridine diphosphate glucuronosyltransferase (UGT) enzymes and renal excretion will result in differences in Cl. There is evidence for females having lower activity of CYP1A2, CYP2E1, and UGT; higher activity of CYP3A4, CYP2A6, and CYP2B6; and no differences in CPY2C9 and CYP2D6 activity. Pharmacodynamic changes can affect both the desired therapeutic effect of a drug as well as its adverse effect profile. The most widely reported sex difference is the higher risk in females for drug-induced long QT syndrome, with two-thirds of all cases of drug-induced torsades occurring in females. Females also have a higher incidence of drug-induced liver toxicity, gastrointestinal adverse events due to NSAIDs, and allergic skin rashes. In conclusion, at the minimum, it is important to take into account size and age as well as co-morbidities in determining the appropriate drug regiment for females, as well as males. There are still large gaps in our knowledge of sex differences in clinical pharmacology and significantly more research is needed.

High abundance synovial fluid proteome: distinct profiles in health and osteoarthritis

The development of increasingly high-throughput and sensitive mass spectroscopy-based proteomic techniques provides new opportunities to examine the physiology and pathophysiology of many biologic fluids and tissues. The purpose of this study was to determine protein expression profiles of high-abundance synovial fluid (SF) proteins in health and in the prevalent joint disease osteoarthritis (OA). A cross-sectional study of 62 patients with early OA (n = 21), patients with late OA (n = 21), and control individuals (n = 20) was conducted. SF proteins were separated by using one-dimensional PAGE, and the in-gel digested proteins were analyzed by electrospray ionization tandem mass spectrometry. A total of 362 spots were examined and 135 high-abundance SF proteins were identified as being expressed across all three study cohorts. A total of 135 SF proteins were identified. Eighteen proteins were found to be significantly differentially expressed between control individuals and OA patients. Two subsets of OA that are not dependent on disease duration were identified using unsupervised analysis of the data. Several novel SF proteins were also identified. Our analyses demonstrate no disease duration-dependent differences in abundant protein composition of SF in OA, and we clearly identified two previously unappreciated yet distinct subsets of protein profiles in this disease cohort. Additionally, our findings reveal novel abundant protein species in healthy SF whose functional contribution to SF physiology was not previously recognized. Finally, our studies identify candidate biomarkers for OA with potential for use as highly sensitive and specific tests for diagnostic purposes or for evaluating therapeutic response.

Modulation of pain by estrogens

It has become increasingly apparent that women suffer a disproportionate amount of pain during their lifetime compared to men. Over the past 15 years, a growing number of studies have suggested a variety of causes for this sex difference, from cellular to psychosocial levels of analysis. From a biological perspective, sexual differentiation of pain appears to occur similarly to sexual differentiation of other phenomena: it results in large part from organizational and activational effects of gonadal steroid hormones. The focus of this review is the activational effects of a single group of ovarian hormones, the estrogens, on pain in humans and animals. The effects of estrogens (estradiol being the most commonly examined) on experimentally induced acute pain vs. clinical pain are summarized. For clinical pain, the review is limited to a few syndromes for which there is considerable evidence for estrogenic involvement: migraine, temporomandibular disorder (TMD) and arthritis. Because estrogens can modulate the function of the nervous, immune, skeletal, and cardiovascular systems, estrogenic modulation of pain is an exceedingly complex, multi-faceted phenomenon, with estrogens producing both pro- and antinociceptive effects that depend on the extent to which each of these systems of the body is involved in a particular type of pain. Forging a more complete understanding of the myriad ways that estrogens can ameliorate vs. facilitate pain will enable us to better prevent and treat pain in both women and men.

Role of age, sex, and obesity in the higher prevalence of arthritis among lower socioeconomic groups: a population-based survey

OBJECTIVE

To compare the prevalence of arthritis among population groups based on demographic, socioeconomic, and body mass index (BMI) characteristics; to investigate the combined influence of these factors on arthritis; and to assess the relationship between self-reported health and psychological distress and arthritis.

METHODS

Data from the Victorian Population Health Survey (n = 7,500) were used in the study. Psychological distress was assessed using the Kessler Psychological Distress scale, and self-reported health was assessed by a single item. Multiple logistic regression was used to investigate the combined influence of demographic and socioeconomic factors and BMI on arthritis.

RESULTS

Overall, 23% of Victorian adults (20% men and 26% women) reported having arthritis. The presence of arthritis was associated with high psychological distress (odds ratio [OR] 1.2; 95% confidence interval [95% CI] 1.1-1.4) and poor self-reported health (OR 1.9; 95% CI 1.7-2.1). Increased prevalence of arthritis was found in older age groups, lower education and income groups, and in people who were overweight or obese. Women had higher risk of arthritis, even after adjustment for age, residence, education, occupation, income, and BMI. Age and BMI independently predicted arthritis for men and women. For men, higher risk of arthritis was also associated with lower income.

CONCLUSION

Arthritis is a highly prevalent condition associated with poor health and high psychological distress. Prevalence of arthritis is disproportionately high among women and individuals from lower socioeconomic backgrounds. As the prevalence of arthritis is predicted to increase, careful consideration of causal factors, and setting priorities for resource allocation for the treatment and prevention of arthritis are required.

Oxidant and anti-oxidant systems of synovial fluid from patients with knee post-traumatic arthritis

It has been suggested that patients with knee post-traumatic arthritis (PA), associated or not to haemarthrosis (HA), display altered oxidant and anti-oxidant systems in their synovial fluid. This study aimed to establish whether this is really the case. Synovial fluid samples were obtained by transdermal arthrocentesis from 69 patients with PA (36 of them had HA) and 22 control subjects. The activities of synovial fluid zinc-copper superoxide dismutase (ZnCuSOD) and manganese superoxide dismutase (MnSOD) isoenzymes, catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione-S-transferase (GST) enzymes, and malondialdehyde (MDA) concentration and synovial fluid viscosity were measured in the study groups. Patients with PA had significantly increased activities of all antioxidant enzymes, except CAT, and MDA concentration than did the controls. However, synovial fluid viscosity was found to be decreased in the study group, mainly in the HA subgroup. Results suggest that excessive free radicals production may exist in synovial fluid of PA patients and may contribute to knee joint destruction.

Gender differences exist in osteoarthritic gait

BACKGROUND

Knee osteoarthritis is 2-3 times more prevalent in females than males. Biomechanical differences in gait may play a role in this gender predisposition. The purpose of this study was to determine if there are gender-based biomechanical differences in the gait patterns of people with knee osteoarthritis.

METHODS

Three-dimensional gait analysis was performed on healthy (18 males and 24 females) subjects and patients with moderate knee osteoarthritis (24 males and 15 females). Kinematics and kinetics at the hip, knee and ankle were calculated. Variables including anthropometrics, stride characteristics, strength, pain, stiffness, function and radiographic disease severity were also quantified. Multivariate statistical techniques and analysis of variance were used to test for main disease effects, main gender effects and disease vs. gender interactions.

FINDINGS

A significant interaction effect between gender and disease was found in the knee flexion angle and the knee moments in the sagittal, frontal and transverse planes. In each of these measures the females exhibited different biomechanics with osteoarthritis, while the osteoarthritic males maintained the same biomechanics as healthy males. This interaction between gender and osteoarthritis was not associated with differences in anthropometrics, stride characteristics, strength, pain, stiffness, function or radiographic disease severity between the populations.

INTERPRETATION

This study has found gait pattern differences between the genders in the osteoarthritic patients that were not apparent in the healthy subjects. This suggests that the biomechanics associated with knee osteoarthritis are gender dependent. Therefore, gender specific design of biomechanical interventions to slow the progression of osteoarthritis should be explored.

Overview of orofacial pain: epidemiology and gender differences in orofacial pain

Chronic orofacial pain is a prevalent problem that encompasses numerous disorders with diverse causes and presenting symptoms. Compared with men, women of reproductive age seek treatment for orofacial pain conditions, as well as other chronic pain disorders more frequently. Important issues have been raised regarding gender and sex differences in genetic, neurophysiologic, and psychosocial aspects of pain sensitivity and analgesia. Efforts to improve our understanding of qualitative sex differences in pain modulation signify a promising step toward developing more tailored approaches to pain management.

Collagen hydrolysate for the treatment of osteoarthritis and other joint disorders: a review of the literature

BACKGROUND

There is a need for an effective treatment for the millions of people in the United States with osteoarthritis (OA), a degenerative joint disease. The demand for treatments, both traditional and non-traditional, will continue to grow as the population ages.

SCOPE

This article reviews the medical literature on the preclinical and clinical research on a unique compound, collagen hydrolysate. Articles were obtained through searches of the PubMed database (www.pubmed.gov) through May 2006 using several pairs of key words (collagen hydrolysate and osteoarthritis; collagen hydrolysate and cartilage; collagen hydrolysate and chondrocytes; collagen hydrolysate and clinical trial) without date limits. In addition, other sources of information, such as abstracts presented at scientific congresses and articles in the German medical literature not available on PubMed, were reviewed and included based on the authors' judgment of their relevance to the topic of the review.

FINDINGS

According to published research, orally administered collagen hydrolysate has been shown to be absorbed intestinally and to accumulate in cartilage. Collagen hydrolysate ingestion stimulates a statistically significant increase in synthesis of extracellular matrix macromolecules by chondrocytes (p < 0.05 compared with untreated controls). These findings suggest mechanisms that might help patients affected by joint disorders such as OA. Four open-label and three double-blind studies were identified and reviewed; although many of these studies did not provide key information--such as the statistical significance of the findings--they showed collagen hydrolysate to be safe and to provide improvement in some measures of pain and function in some men and women with OA or other arthritic conditions.

CONCLUSION

A growing body of evidence provides a rationale for the use of collagen hydrolysate for patients with OA. It is hoped that ongoing and future research will clarify how collagen hydrolysate provides its clinical effects and determine which populations are most appropriate for treatment with this supplement.

Epidemiological Aspects of Rheumatoid Arthritis: The Sex Ratio

Many rheumatic diseases, including rheumatoid arthritis (RA) are more frequent in females than males. The objective of this article was to examine the female versus male perspective regarding prevalence/incidence, etiological factors, disease severity/outcomes, access to therapy and therapeutic responses. We also present results from some new analyses from the patient registers in Oslo to supplement existing literature in this area. We found that the prevalence of RA is higher in females than males, the incidence is 4-5 times higher below the age of 50, but above 60-70 years the female/male ratio is only about 2. Smoking is a consistent predictor of RA in males, but findings have been more inconsistent in females. We could not confirm that health status is worse in females than males when corrections were made for different disease duration and for the underlying tendency of healthy females to report worse subjective health status than males. Some studies and data presented here indicate that females have less access to health services. We also found that female sex reduces the likelihood of achieving treatment response with methotrexate and anti-tumor necrosis factor (anti-TNF) drugs by 30-50%. More research is needed to fully describe the differences between males and females regarding epidemiological data.

Estradiol and progesterone differentially regulate formalin-induced nociception in ovariectomized female rats

Clinical and preclinical studies have found sex-specific differences in the discrimination and perception of inflammatory stimuli. The emerging picture suggests that the biological basis of these differences resides in the regulatory activity of gonadal hormones in the central nervous system. This study describes the effects of ovarian hormones in inflammatory pain processes. Ovariectomized rats received estradiol and/or progesterone, and the number of paw flinches was measured after 1, 2.5 or 5% formalin administration. Both estradiol and progesterone altered the number of flinches only after 1% formalin administration. Estradiol significantly reduced the overall number of flinches during Phase II of the formalin nociceptive response while progesterone attenuated Phase I of the response. After co-administration of estradiol and progesterone, progesterone reversed estradiol's analgesic effect in Phase II, however, estradiol did not reverse progesterone's analgesic activity in Phase I. To determine if estradiol effects are receptor-mediated, tamoxifen (selective estrogen receptor mediator, 15 mg/kg) or alpha-estradiol (an inactive isomer of estradiol, 20 microg) were utilized. Tamoxifen decreased the number of formalin-induced flinches during Phase II while alpha-estradiol did not affect any formalin-induced responses. When co-administered with estradiol, tamoxifen failed to reverse estradiol's effect, suggesting both tamoxifen and estradiol activate similar intracellular mechanisms. Although Western blot analysis detected the presence of estradiol alpha and beta and progesterone B receptors in the spinal cord, hormone replacement treatments had no effects on the levels of these receptors. We postulate that the mechanisms by which estradiol and progesterone induce analgesia occur through the activation of their receptor at the spinal cord level.

Individual differences in pain responses

The experience of pain is characterized by tremendous inter-individual variability. Indeed, an identical noxious stimulus can produce vastly different pain responses across individuals. Historically, scientists have regarded this variability as a nuisance; however, substantial data suggest that these individual differences may provide valuable information that can be used to enhance clinical management of pain. This paper discusses several factors that contribute to individual differences in pain perception, including demographic (ie, sex, age, and ethnicity), genetic, and psychosocial variables. These factors are discussed in the context of the biopsychosocial model of pain, which posits that pain perception is influenced by interactions among biologic, psychosocial, and sociocultural factors. Finally, the clinical and scientific implications of individual differences in pain are discussed.