Males and females differ in their immunological responses to foreign and self-antigens and show distinctions in innate and adaptive immune responses. Certain immunological sex differences are present throughout life, whereas others are only apparent after puberty and before reproductive senescence, suggesting that both genes and hormones are involved. Furthermore, early environmental exposures influence the microbiome and have sex-dependent effects on immune function. Importantly, these sex-based immunological differences contribute to variations in the incidence of autoimmune diseases and malignancies, susceptibility to infectious diseases and responses to vaccines in males and females. Here, we discuss these differences and emphasize that sex is a biological variable that should be considered in immunological studies.

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Sex differences in immune responses

Summary Guidance is provided in a European setting on the assessment and treatment of postmenopausal women with or at risk from osteoporosis. Introduction The European Foundation for Osteoporosis and Bone disease (subsequently the International Osteopo- rosis Foundation) published guidelines for the diagnosis and management of osteoporosis in 1997. This manuscript updates these in a European setting. Methods The following areas are reviewed: the role of bone mineral density measurement for the diagnosis of osteoporo- sis and assessment of fracture risk; general and pharmaco- logical management of osteoporosis; monitoring of treatment; assessment of fracture risk; case finding strategies; investigation of patients; health economics of treatment. Results and conclusions A platform is provided on which specific guidelines can be developed for national use.

/pdf/european-guidance-for-the-diagnosis-and-management-of-bexvs3o205.pdf

European guidance for the diagnosis and management of osteoporosis in postmenopausal women

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(02)08761-5.pdf

Diagnosis of osteoporosis and assessment of fracture risk

The diagnosis of osteoporosis is based on the measurement of bone mineral density (BMD). There are a number of clinical risk factors that provide information on fracture risk over and above that given by BMD. The assessment of fracture risk thus needs to be distinguished from diagnosis to take account of the independent value of the clinical risk factors. These include age, a prior fragility fracture, a parental history of hip fracture, smoking, use of systemic corticosteroids, excess alcohol intake and rheumatoid arthritis. The independent contribution of these risk factors can be integrated by the calculation of fracture probability with or without the use of BMD. Treatment can then be offered to those identified to have a fracture probability greater than an intervention threshold.

Assessment of fracture risk.

R. P. Heaney, S. Abrams, B. Dawson-Hughes, A. Looker, R. Marcus, V. Matkovic and C. Weaver Creighton University, Omaha, NE; Children’s Nutrition Research Center, Houston, TX; Tufts University, Boston, MA; National Osteoporosis Foundation, Washington, DC; National Center for Health Statistics, Hyattsville, MD; Stanford University, Palo Alto, CA; Ohio State University, Columbus, OH; and Purdue University, West Lafayette, IN, USA

Peak bone mass

The TLR-mediated response of plasmacytoid dendritic cells is positively regulated by estradiol in vivo through cell-intrinsic estrogen receptor α signaling

Obesity and postmenopausal bone loss: the influence of obesity on vertebral density and bone turnover in postmenopausal women.

SUMMARY
obfective We wished to assess the predictive value of the main clinical risk factors for osteoporosis over a low vertebral bone mineral density

design A cross-sectional study was made of a cohort of peri and post-menopausal women (mean age, 54 years)

patients One thousand, five hundred and sixty-five normal white women were selected from among the women referred to our menopause clinic for screening and prevention of osteoporosis

measurements Each woman had replied to a detailed standardized questionnaire including the main clinical risk factors and had her bone density measured using dual photon absorptiometry

results The predictive value for a low vertebral bone mineral density (2 SD below the normal young adult value) was assessed for 15 historical and anthropometric vari-ables. Among these, age, age at menarche, weight, height, menopause and its duration, were independant predictors of a low bone mineral density, in a multiple logistic regression analysis. Odds ratios were calculated for each of these variables, weight, menopause and its duration being the three most influential variables. At best this model makes it possible to correctly classify 73% of women with a low bone mineral density and 66% of those with a normal bone mineral density. If this model Is used for screening, it could possibly save 25% of bone denslto-metry examinations

conclusions Direct bone densitometry remains indispensable to assess osteoporosis risk, since risk factors alone are not sufficient for accurate delineation of either low or normal bone mineral density

Assessment of the risk of post-menopausal osteoporosis using clinical factors

The purpose of this study was to evaluate prospectively the evolution of femoral and vertebral bone mineral density (BMD) in hypothyroid subjects treated with replacement doses (mean +/- SD dose of L-thyroxine = 135 +/- 32 micrograms/day) as compared to an untreated group. Vertebral bone density was also measured in other patients who had been treated for at least 2 years with either suppressive (mean dose = 154 +/- 36 micrograms/day, n = 28) or replacement doses (mean dose = 104 +/- 52 micrograms/day, n = 21) according to the thyrotrophin response (TSH) to the thyrotrophin releasing hormone (TRH) administration. In primary hypothyroid patients, a mean decrease of 5.4% (P less than 0.01) for vertebral BMD, 7.3% (P less than 0.01) for trochanter and 7% (P less than 0.001) for femoral neck was observed after 1 year of treatment. This loss was unrelated either to age or to menopausal status (ANOVA). A clinical and hormonal state of euthyroidism was reached since the 3rd month of treatment. Fasting urinary calcium/creatinine excretion was increased significantly (P less than 0.05) at the 3rd month, and plasma osteocalcin (OC) increased significantly from the 3rd month onwards (P less than 0.05) up to the 12th month (P less than 0.025). In the cross-sectional study, vertebral BMD was not significantly different from age-matched normal values in patients receiving either substitutive or suppressive doses of LT4. These results suggest that in the case of primary hypothyroidism even appropriate thyroid replacement therapy could lead during the first year of treatment to a significant reduction in vertebral and femoral BMD. However, the fact that an increased fracture rate has not been documented in long-term treated patients, and the results of our cross-sectional study, suggest that this bone mass reduction could be transient and reversible due to new bone formation at the end of the resorptive sequence.

Bone mineral density and thyroid hormone therapy

This study aimed to assess the changes in vertebral bone mineral density (BMD) after cessation of hormone replacement therapy (HRT) in postmenopausal women who had been treated on a long-term basis. Fifty healthy postmenopausal women who had been followed both during the course of HRT and after cessation of treatment in our menopause clinic were included in this study. All women had started HRT within the first 3 years after the postmenopause and had received HRT (either 1.5 mg/day of 17β-estradiol given percutaneously or 50 μg/day of 17β-estradiol given as a transdermal patch, combined in all women with natural progesterone or a 19-norprogesterone derivative) for a mean 5 ± 2.4 years. In all women, vertebral BMD was assessed during the course of HRT up to the last 6 months before estrogen withdrawal, then at least once within the first 18 months after cessation of treatment. Of the initial population, 30 women were additionally reviewed later on and up to 8 years after cessation of treatment (mean duration of follow-up for the whole population: 3.9 ± 1.7 years). Rates of changes in vertebral BMD were compared with those determined in a group of healthy untreated women who had been followed within the first years of postmenopause during the same time period as the study population. In the study group, bone loss was found to accelerate within the first 2 years after HRT withdrawal and the annual rate of loss was identical to that which occurs within the first 2 years of postmenopause in untreated women (−1.64%± 1.3% vs −1.52 ± 0.9%, NS). Beyond this first 2-year time period, the annual rate of bone loss decreased as a function of time following cessation of treatment, as was observed following the menopause in untreated women (between 3 and 5 years: −0.83%+ 1.35% in the study group vs −0.70%± 0.8% in the control group, NS). On average, 3 years after cessation of HRT mean vertebral BMD when expressed as a Z-score was significantly higher (−0.13 vs −0.89, p<0.01) than at baseline, before HRT was started, which suggested a lasting beneficial effect on bone mass. However, even though our findings do not support the hypothesis that bone loss might continue to be accelerated several years after cessation of treatment we cannot fully address the question as to whether any residual benefit on bone mass over a longer period of time may be observed. In conclusion, the pattern of bone loss observed after cessation of estrogen therapy was found to be comparable to that which occurs in younger women within the first years after the menopause. Such a pattern needs to be kept in mind when the decision to stop HRT is taken, especially in women who were given HRT to prevent osteoporosis. The issue of assessing their risk of fracture several years after cessation of treatment thus needs to be addressed.

F. Tremollieres

Papers

The TLR-mediated response of plasmacytoid dendritic cells is positively regulated by estradiol in vivo through cell-intrinsic estrogen receptor α signaling

Obesity and postmenopausal bone loss: the influence of obesity on vertebral density and bone turnover in postmenopausal women.

Assessment of the risk of post-menopausal osteoporosis using clinical factors

Bone mineral density and thyroid hormone therapy

Withdrawal of hormone replacement therapy is associated with significant vertebral bone loss in postmenopausal women.