Association between caffeine intake and bone mass among young women: potential effect modification by depot medroxyprogesterone acetate use

U.S. Medical Eligibility Criteria for Contraceptive Use, 2024

The 2024 U.S. Medical Eligibility Criteria for Contraceptive Use (U.S. MEC) comprises recommendations for the use of specific contraceptive methods by persons who have certain characteristics or medical conditions. These recommendations for health care providers were updated by CDC after review of the scientific evidence and a meeting with national experts in Atlanta, Georgia, during January 25-27, 2023. The information in this report replaces the 2016 U.S. MEC (CDC. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. MMWR 2016:65[No. RR-3]:1-103). Notable updates include 1) the addition of recommendations for persons with chronic kidney disease; 2) revisions to the recommendations for persons with certain characteristics or medical conditions (i.e., breastfeeding, postpartum, postabortion, obesity, surgery, deep venous thrombosis or pulmonary embolism with or without anticoagulant therapy, thrombophilia, superficial venous thrombosis, valvular heart disease, peripartum cardiomyopathy, systemic lupus erythematosus, high risk for HIV infection, cirrhosis, liver tumor, sickle cell disease, solid organ transplantation, and drug interactions with antiretrovirals used for prevention or treatment of HIV infection); and 3) inclusion of new contraceptive methods, including new doses or formulations of combined oral contraceptives, contraceptive patches, vaginal rings, progestin-only pills, levonorgestrel intrauterine devices, and vaginal pH modulator. The recommendations in this report are intended to serve as a source of evidence-based clinical practice guidance for health care providers. The goals of these recommendations are to remove unnecessary medical barriers to accessing and using contraception and to support the provision of person-centered contraceptive counseling and services in a noncoercive manner. Health care providers should always consider the individual clinical circumstances of each person seeking contraceptive services. This report is not intended to be a substitute for professional medical advice for individual patients; when needed, patients should seek advice from their health care providers about contraceptive use.

The relationship between caffeine and its metabolites and bone mineral density in postmenopausal women: a cross-sectional analysis from the NHANES database

We aim to explore the association between caffeine and its metabolites and bone mineral density (BMD) in postmenopausal women. Data of 4286 postmenopausal women were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 2009-14 in this cross-sectional study. Weighted linear regression and stepwise regression analyses were used to screen the covariates. Weighted univariate and multivariate linear regression analyses were used to explore the associations between caffeine and its metabolites and BMD. The evaluation index was estimated value (β) with 95 % confidence intervals (CIs). We also explored these relationships in age subgroups. The median BMD level among the eligible women was 0⋅7 gm/cm2. After adjusting for covariates including age, body mass index (BMI), fat intake, Calcium (Ca) supplements, diabetes mellitus (DM), angina pectoris, parental history of osteoporosis (OP), anti-osteoporosis therapy, poverty income ratio (PIR), vitamin D (VD) supplements, coronary heart disease (CHD), and previous fracture, we found that caffeine intake was not significantly related to the BMD reduction (β = 0, P = 0⋅135). However, caffeine metabolites, including MethyluricAcid3, MethyluricAcid7, MethyluricAcid37, Methylxanthine3, and Methylxanthine37, were negatively associated with the BMD (all P < 0⋅05). In addition, MethyluricAcid37 and Methylxanthine37 were negatively associated with BMD in females aged <65 years old, while MethyluricAcid3 and Methylxanthine3 were noteworthy in those who aged ≥65 years old. The roles of caffeine and its metabolites in BMD reduction and OP in postmenopausal women needed further exploration.

Clinical Evidence of the Benefits of Phytonutrients in Human Healthcare

Phytonutrients comprise many different chemicals, including carotenoids, indoles, glucosinolates, organosulfur compounds, phytosterols, polyphenols, and saponins. This review focuses on the human healthcare benefits of seven phytochemical families and highlights the significant potential contribution of phytonutrients in the prevention and management of pathologies and symptoms in the field of family health. The structure and function of these phytochemical families and their dietary sources are presented, along with an overview of their potential activities across different health and therapeutic targets. This evaluation has enabled complementary effects of the different families of phytonutrients in the same area of health to be recognized.

Dietary Patterns of Greek Adults and Their Associations with Serum Vitamin D Levels and Heel Quantitative Ultrasound Parameters for Bone Health

The aim of this study is to investigate the dietary patterns which indicate the nutritional habits of Greek adults and their effects on serum 25(OH)D levels and quantitative ultrasound (QUS) parameters for bone health. This study is part of OSTEOS, an observational cross-sectional study. In total, 741 adults from rural and urban areas throughout Greece were recruited. A validated food frequency questionnaire (FFQ) was used for assessment of the population’s dietary habits. Serum 25(OH)D was measured by enzyme immunoassay; QUS parameters were assessed with an Achilles device. Principal component analysis (PCA) was carried out for dietary pattern determination, and univariate analysis of variance was used for the assessment of 25(OH)D, broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) determinants. Six dietary patterns explain 52.2% of the variability of Greek adults’ nutritional habits. The ‘vegetables–fruit’ dietary pattern explains the biggest rate of variability. Determinants of serum 25(OH)D are body mass index (BMI), elderly status, summer sun exposure, organized physical activity, a ‘healthy’ pattern in winter months, and adherence to a ‘sweet’ pattern. Determinants of QUS parameters are age, BMI, sedentary time, organized physical activity participation, and adherence to a ‘healthy’ pattern.

β-Estradiol antagonizes the inhibitory effects of caffeine in BMMSCs via the ERβ-mediated cAMP-dependent PKA pathway

Caffeine negatively mediates bone homeostasis to cause bone loss and even osteoporosis. This phenomenon occurs in postmenopausal women with estrogen deficiency but not in healthy young women. In this study, we determined whether the effects of caffeine on bone homeostasis were antagonized by estrogen and the underlying mechanisms. In particular, because high levels of cAMP, an important second messenger, have been observed in postmenopausal women suffering from osteoporosis, we examined the role of cAMP in the effects of caffeine on bone homeostasis. In vivo study showed that caffeine accelerated bone loss in osteoporotic rats, whereas β-estradiol blunted the negative effect of caffeine on bone. In vitro study, we harvested bone marrow-derived mesenchymal stromal cells (BMMSCs) from osteoporotic rats. We found that caffeine and β-estradiol inversely affected BMMCSs proliferation, apoptosis, osteogenic lineage commitment, extracellular matrix synthesis and mineralization. These parameters were assessed according to the expression levels of osteogenic markers, alkaline phosphatase activity and Alizarin red staining. The deleterious effects of caffeine on BMMSCs were blunted by β-estradiol. The cAMP-dependent PKA pathway was found to be involved in regulating caffeine/β-estradiol-mediated cell growth, survival and osteogenesis. Additionally, after estrogen receptor (ER) β knockdown, the antagonistic effects of β-estradiol on caffeine were nearly abolished. These results indicated that by binding to ERβ, β-estradiol antagonizes the negative impacts of caffeine on cell growth and osteogenic differentiation in BMMSCs through the cAMP-dependent PKA signaling pathway.

Canadian Contraception Consensus (Part 3 of 4): Chapter 8 - Progestin-Only Contraception

OBJECTIVE

To provide guidelines for health care providers on the use of contraceptive methods to prevent pregnancy and on the promotion of healthy sexuality.

OUTCOMES

Overall efficacy of cited contraceptive methods, assessing reduction in pregnancy rate, safety, ease of use, and side effects; the effect of cited contraceptive methods on sexual health and general well-being; and the relative cost and availability of cited contraceptive methods in Canada.

EVIDENCE

Published literature was retrieved through searches of Medline and The Cochrane Database from January 1994 to January 2015 using appropriate controlled vocabulary (e.g., contraception, sexuality, sexual health) and key words (e.g., contraception, family planning, hormonal contraception, emergency contraception). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from January 1994 to January 2015. Searches were updated on a regular basis in incorporated in the guideline to June 2015. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of the evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). CHAPTER 8: PROGESTIN-ONLY CONTRACEPTION: Summary Statements Recommendations.

Long-term coffee consumption in relation to fracture risk and bone mineral density in women

High consumption of coffee has been suggested to reduce the risk of some late-onset diseases and death but also to contribute to the development of osteoporotic fractures. Results of previous fracture studies have been inconsistent, and a comprehensive study is needed. The longitudinal population-based Swedish Mammography Cohort, including 61,433 women born in 1914-1948, was followed up from 1987 through 2008. Coffee consumption was assessed with repeated food frequency questionnaires. During follow-up, 14,738 women experienced fracture of any type, and 3,871 had a hip fracture. In a subcohort (n = 5,022), bone density was measured and osteoporosis determined (n = 1,012). After multivariable adjustment, there was no evidence of a higher rate of any fracture (hazard ratio per 200 mL coffee = 0.99; 95% confidence interval: 0.98, 1.00) or hip fracture (hazard ratio per 200 mL coffee = 0.97, 95% confidence interval: 0.95, 1.00) with increasing coffee consumption. A high coffee intake (≥4 cups daily) versus a low intake (<1 cup daily) was associated with a 2%-4% lower bone density, depending on site (P < 0.001), but the odds ratio for osteoporosis was only 1.28 (95% confidence interval: 0.88, 1.87). Thus, high coffee consumption was associated with a small reduction in bone density that did not translate into an increased risk of fracture.

Calcium and caffeine interaction in increased calcium balance in ovariectomized rats

OBJECTIVE: This study investigated the effects of caffeine intake associated with inadequate or adequate calcium intake in laparotomized or ovariectomized rats by means of the calcium balance. Forty adults Wistar rats were ovariectomized or laparotomized. METHODS: The animals (n=40) were randomly placed in eight groups receiving the AIN-93 diet with 100% or 50% of the recommended calcium intake with or without added caffeine (6mg/kg/day). The animals were kept in individuals metabolic cages at a temperature of 24°±2ºC, light/dark cycles of 12/12 hours, and deionized water available ad libitum. On the 8th week of the experiment, food consumption was measured and 24-hour urine and 4-day feces were collected to determine calcium balance [Balance=Ca intake-(Urinary Ca+Fecal Ca)]. RESULTS: Animals with adequate calcium intake presented higher balances and rates of calcium absorption and retention (p<0.05) than those with inadequate calcium intake, regardless of caffeine intake (p<0.05). Caffeine intake did not affect urinary calcium excretion but increased balance (p<0.05) in the groups with adequate calcium intake. CONCLUSION: Adequate calcium intake attenuated the negative effects of estrogen deficiency and improved calcium balance even in the presence of caffeine.

Differentiation of mesenchymal stem cells to osteoblasts and chondrocytes: a focus on adenosine receptors

Skeletogenesis, either during development, post-injury or for maintenance, is a carefully coordinated process reliant on the appropriate differentiation of mesenchymal stem cells. Some well described, as well as a new regulator of this process (adenosine receptors), are alike in that they signal via cyclic-AMP (cAMP). This review highlights the known contribution of cAMP signalling to mesenchymal stem cell differentiation to osteoblasts and to chondrocytes. Focus has been given to how these regulators influence the commitment of the osteochondroprogenitor to these separate lineages.

Predictors of bone mineral density in a convenience sample of young Caucasian adults living in southern Ontario

Osteoporosis is a major public health concern in Canada and worldwide. Although much is known about bone health in older adults, little is known about bone health in young, healthy Canadian men and women. The objectives of this research were to describe bone mineral density (BMD) of young, healthy adults living in southern Ontario, Canada, and to identify predictors of BMD in this population. Two-hundred and fifty-eight Caucasian men and women aged 18–33 years completed health and physical activity questionnaires along with a calcium and vitamin D specific food frequency questionnaire. Height and mass were measured. BMD of the total hip, femoral neck, spine, and total body was measured using dual energy X-ray absorptiometry. Among men, body mass, weight-bearing physical activity, and calcium intake were significant predictors of BMD. Among women, body mass, calcium intake, and family history of osteoporosis significantly predicted log BMD. The predictors of BMD in young Canadian men and women identified in this study may inform the development of longitudinal studies designed to examine the influence of lifestyle factors on BMD in young adults.

Reciprocal roles between caffeine and estrogen on bone via differently regulating cAMP/PKA pathway: the possible mechanism for caffeine-induced osteoporosis in women and estrogen's antagonistic effects

Caffeine is consumed by most people in Europe and North America. As a risk factor for osteoporosis, caffeine has been reported to decrease bone mineral density, negatively influence calcium absorption and increase the risk of bone fracture in women. Except for the epidemiological observations and several studies which proved caffeine's unfavorable effects on osteoblast proliferation and impaired ability to form bone, little mechanism is known for the caffeine-induced osteoporosis. Since our unpublished studies showed that the precursor cells of osteoblasts, bone marrow-derived mesenchymal stem cells (BMSCs), were more sensitive than osteoblasts when exposed to the same dose of caffeine. We herein hypothesize that MSCs may be the primary target cells for caffeine-induced osteoporosis. It is well established that increasing cyclic 3',5'-adenosine monophosphate (cAMP) can regulate the expression of key genes involved in bone metabolism, including Cbfa1, PPARgamma, RANKL and OPG. We thereby propose the hypothesis that caffeine, a known inhibitor of cAMP phosphodiesterase, may affect bone metabolism by activating cAMP-dependent protein kinase A (PKA) pathway. In addition, considering the fact observed in epidemiology that caffeine's negative effects on bone only occurred in postmenopausal women and the inverse roles of caffeine and estrogen on bone metabolism, we postulate that caffeine may exert its undesirable influences on bone only in absence or low level of estrogen in vivo and estrogen may antagonize the adverse effect of caffeine on bone. Since several studies have demonstrated that estrogen may have ability to temper the biological effects of cAMP stimulators' roles on bone through cAMP to regulate some important genes' expression in bone metabolism. We assume that estrogen may block cAMP-dependent PKA pathway which is shared by caffeine, to exhibit its antagonistic roles.

Association between long-term consumption of soft drinks and variables of bone modeling and remodeling in a sample of healthy German children and adolescents

BACKGROUND

Soft drinks are thought to displace milk in diets of children and adolescents and therefore might affect variables of bone modeling and remodeling.

OBJECTIVE

We assessed the association between long-term consumption of several types of soft drinks and bone variables in children and adolescents.

DESIGN

Long-term dietary data from 3-d weighed dietary records collected by 228 healthy children and adolescents enrolled in the DONALD Study in 4 y of study participation were used for data analysis. Variables of bone modeling and remodeling of the radius were assessed by using peripheral quantitative computed tomography.

RESULTS

After adjustment for age, sex, total energy intake, muscle area, BMI SD scores, and growth velocity, long-term consumption of all soft drinks and uncaffeinated soft drinks was negatively associated with bone mineral content (P < 0.05), cortical area (P < 0.05), and polar strength strain index (P < 0.05), all of which reflect a combination of bone modeling and remodeling. Long-term consumption of caffeinated soft drinks was negatively associated with polar strength strain index (P < 0.01) and periosteal circumference (P < 0.05), which reflect bone modeling. Milk intake was positively associated with polar strength strain index (P < 0.05). Consumption of all soft drinks was negatively associated with total protein and milk intake, but was not associated with potential renal acid load.

CONCLUSIONS

Long-term consumption of caffeinated and uncaffeinated soft drinks appears to have bone catabolic effects in boys and girls. This effect is mainly mediated by the negative association with total protein intake and is not primarily based on milk displacement.