Meditative practices, stress and sleep among students studying complementary and integrative health: a cross-sectional analysis.

BACKGROUND: The International Cohort on Lifestyle Determinants of Health (INCLD Health) is an ongoing, prospective cohort study assessing the health behaviours and lifestyles of higher education students, including their use of specialty diets and complementary and integrative health (CIH) practices. PURPOSE: This cross-sectional analysis of the INCLD Health cohort aims to (1) evaluate the associations between perceived stress, sleep disturbance, and meditative practices with diurnal salivary free cortisol and (2) evaluate the associations of meditative practices as well as mind-body practices with perceived stress and sleep disturbance. METHODS: Serial multivariable linear regression models, adjusting for sociodemographic and lifestyle behaviours, were used to assess associations of (1) perceived stress, sleep disturbance, and meditative practices with salivary cortisol, and (2) meditative practices as well as mind-body practices with perceived stress and sleep disturbance. Meditative and mind-body practices were evaluated using a stress-management and self-care survey; perceived stress and sleep disturbance were evaluated using the 10-item Perceived Stress Scale (PSS), and the patient reported outcome measures information system-29 (PROMIS-29) sleep sub-score respectively. Salivary cortisol was collected at 4 time points over a 24-hour period and area under the curve (AUC) calculations conducted. RESULTS: 82.5% (n = 80) of participants utilized at least monthly meditative practices. Greater disturbed sleep, but not perceived-stress, meditative, nor mind-body practices was independently associated with increased AUC cortisol (b = 0.02, 95% CI: 0.002-0.05, p = 0.03) after adjusting for age, sex, race, ethnicity, and BMI. Neither meditative nor mind-body practices were associated with perceived stress or disturbed sleep. CONCLUSIONS: Among INCLD Health participants, greater sleep disturbance, but not perceived stress or meditative practices were associated with daytime cortisol.

Validation of dried blood spot sample modifications to two commercially available COVID-19 IgG antibody immunoassays.

Aim: Coronavirus disease 2019 antibody testing often relies on venous blood collection, which is labor-intensive, inconvenient and expensive compared with finger-stick capillary dried blood spot (DBS) collection. The purpose of our work was to determine if two commercially available anti-severe acute respiratory syndrome coronavirus 2 enzyme-linked immunosorbent assays for IgG antibodies against spike S1 subunit and nucleocapsid proteins could be validated for use with DBS. Materials & methods: Kit supplied reagents were used to extract DBS, and in-house DBS calibrators were included on every run. Results: Positive/negative concordance between DBS and serum was 100/99.3% for the spike S1 subunit assay and 100/98% for the nucleocapsid assay. Conclusion: Validation of the DBS Coronavirus disease 2019 IgG antibody assays demonstrated that serum and DBS can produce equivalent results with minimal kit modifications.

Salivary aldosterone and cortisone respond differently to high- and low-psychologically stressful soccer competitions.

Aldosterone and cortisone are released in response to physical and psychological stress. However, aldosterone and cortisone responses in children engaged in physical competition have not been described. We examined salivary aldosterone and salivary cortisone responses among Hong Kongese boys, aged 8-11 years, during (1) a soccer match against unknown competitors (N = 84, high psychological stress condition) and (2) an intrasquad soccer scrimmage against teammates (N = 81, low psychological stress condition). Aldosterone levels increased during the soccer match and intrasquad soccer scrimmage conditions, consistent with the view that aldosterone responds to physical stress. During the soccer match, winning competitors experienced larger increases in aldosterone compared to losing competitors, indicating that the degree of aldosterone increase was attenuated by match outcome. Cortisone increased during the soccer match and decreased during the intrasquad soccer scrimmage. Competitors on teams that resulted in a tie had larger cortisone increases compared to winners or losers. These findings highlight that the degree of cortisone change is related to boy's cognitive appraisal of the competitor type (i.e., teammates vs. unknown competitors) and the competitive nature of the game (e.g., tie). These results shed new light on adrenal hormone mediators of stress and competition during middle childhood.

4-Hydroxy estrogen metabolite, causing genomic instability by attenuating the function of spindle-assembly checkpoint, can serve as a biomarker for breast cancer.

Sex hormone metabolism is altered during mammary gland tumorigenesis, and different metabolites may have different effects on mammary epithelial cells. This study aimed to evaluate associations between urinary sexual metabolite levels and breast cancer risk among premenopausal women of Mainland China. The molecular metabolism of the cancer-related metabolites was also explored based on the clinical data. The sex hormone metabolites in the urine samples of patients with breast cancer versus normal healthy women were analyzed comprehensively. Among many alterations of sex hormone metabolisms, 4-hydroxy estrogen (4-OH-E) metabolite was found to be significantly increased in the urine samples of patients with breast cancer compared with the normal healthy controls. This was the most important risk factor for breast cancer. Several experiments were conducted in vitro and in vivo to probe this mechanism. 4-Hydroxyestradiol (4-OH-E2) was found to induce malignant transformation of breast cells and tumorigenesis in nude mice. At the molecular level, 4-OH-E2 compromised the function of spindle-assembly checkpoint and rendered resistance to the anti-microtubule drug. Further, transgenic mice with high expression of CYP1B1, a key enzyme of 4-hydroxy metabolites, were established and stimulated with estrogen. Cancerous tissue was found to appear in the mammary gland of transgenic mice.

Does testosterone impair men's cognitive empathy? Evidence from two large-scale randomized controlled trials.

The capacity to infer others' mental states (known as 'mind reading' and 'cognitive empathy') is essential for social interactions across species, and its impairment characterizes psychopathological conditions such as autism spectrum disorder and schizophrenia. Previous studies reported that testosterone administration impaired cognitive empathy in healthy humans, and that a putative biomarker of prenatal testosterone exposure (finger digit ratios) moderated the effect. However, empirical support for the relationship has relied on small sample studies with mixed evidence. We investigate the reliability and generalizability of the relationship in two large-scale double-blind placebo-controlled experiments in young men (n = 243 and n = 400), using two different testosterone administration protocols. We find no evidence that cognitive empathy is impaired by testosterone administration or associated with digit ratios. With an unprecedented combined sample size, these results counter current theories and previous high-profile reports, and demonstrate that previous investigations of this topic have been statistically underpowered.

The Relationship Between Progesterone, Sleep, and LH and FSH Secretory Dynamics in Early Postmenarchal Girls.

CONTEXT: During puberty, LH pulse frequency increases during sleep; in women, LH pulse frequency slows during sleep in the early/middle follicular phase (FP) of the menstrual cycle. The origin and significance of this developmental transition are unknown. OBJECTIVE: To determine the relationship between progesterone (P4) exposure, sleep-related slowing of LH pulses in the FP, and the intercycle FSH rise, which promotes folliculogenesis, in early postmenarchal girls. METHODS: 23 girls (gynecologic age 0.4 to 3.5 years) underwent hormone measurements and pelvic ultrasounds during two consecutive cycles and one frequent blood sampling study with concurrent polysomnography during the FP. RESULTS: Subjects demonstrated one of four patterns during cycle 1 that represent a continuum of P4 exposure: ovulatory cycles with normal or short luteal phase lengths or anovulatory cycles ± follicle luteinization. Peak serum P4 and urine pregnanediol (Pd) in cycle 1 were inversely correlated with LH pulse frequency during sleep in the FP of cycle 2 (r = -0.5; P = 0.02 for both). The intercycle FSH rise and folliculogenesis in cycle 2 were maintained after anovulatory cycles without P4 or Pd exposure or nocturnal slowing of LH pulse frequency in the FP. CONCLUSIONS: During late puberty, rising P4 levels from follicle luteinization and ovulation may promote a slower LH pulse frequency during sleep in the FP. However, a normal FSH rise and follicle growth can occur in the absence of P4-associated slowing. These studies therefore suggest that an immature LH secretory pattern during sleep is unlikely to contribute to menstrual irregularity in the early postmenarchal years.

Healthy Post-Menarchal Adolescent Girls Demonstrate Multi-Level Reproductive Axis Immaturity.

Context: Menstrual irregularity after menarche has been attributed to immature estrogen positive feedback activity (E+FB) but data are conflicting. Objective: To determine the hypothalamic-pituitary-ovarian contributions to menstrual irregularity in adolescents. Methods: Twenty-three healthy girls [aged 12.8 to 17.6 years; 0.4 to 3.5 years postmenarche; body mass index (BMI) percentile, 41.0 to 99.3] underwent serial hormone measurements and pelvic ultrasounds during two consecutive menstrual cycles. Hormones and follicle growth were compared with 65 adult historic controls with ovulatory cycles (OVs). Results: Girls had anovulatory cycles (ANOVs; 30%), OVs with a short luteal phase (short OVs; 22%), or OVs with normal luteal phase (normal OVs; 48%) without differences in cycle length, chronologic or gynecologic age, or BMI. Adolescents showed a spectrum of E+FB [midcycle LH adjusted for preovulatory estradiol (E2)]; only normal OV girls were comparable to adults. All OV girls had lower E2, progesterone, and gonadotropins during the luteal phase and luteal-follicular transition compared with adults. Normal OV girls also had lower follicular phase LH and FSH levels, a longer follicular phase, a slower dominant follicle growth rate, and smaller estimated preovulatory follicle size than adults. Follicular phase E2 and inhibin B levels were lower in normal OV girls than in adults even after adjusting for differences in FSH and follicle size. Conclusions: Early postmenarchal girls with normal OVs demonstrate mature E+FB but continue to have lower gonadotropin levels, diminished ovarian responsiveness, and decreased corpus luteum sex steroid synthesis compared with adults, indicating that reproductive axis maturity requires coordinated development of all components of the hypothalamic-pituitary-ovarian axis.

Salivary steroid hormone responses to dyadic table tennis competitions among Hong Kongese juvenile boys.

OBJECTIVES: Little is known about salivary steroid hormone responses to dyadic competition among prepubescent boys. The current study explored pre-match and post-match testosterone, dehydroepiandrosterone (DHEA), androstenedione, and cortisol among 22 ethnically Chinese, Hong Kongese table tennis athletes, aged 8-11 years, during dyadic competition against peers. These data provide novel comparative insight into boys' hormone responses when participating in similar forms of competition to that of adults. METHODS: Measures of salivary steroid hormones, age, outcome, and participant's self-reported perceived performance were obtained. Pre-match salivary steroid hormones and competition-induced steroid hormone changes were explored to further assess overall hypothalamic-pituitary-adrenal axis activity. RESULTS: Cortisol decreased for most participants, whereas testosterone measures were below the sensitivity of the assay. DHEA and androstenedione did not significantly change during the table tennis exhibitions and were unrelated to independent performance variables. Correlational analyses indicated that competition-induced androstenedione and cortisol change were positively related. CONCLUSIONS: Findings show that juvenile boys' steroid hormone responses during dyadic athletic competition differ in comparison to adult males, in whom cortisol and testosterone tend to rise. Lack of significant DHEA and androstenedione change during the table tennis competition differs from our previous work that showed DHEA and androstenedione were sensitive to more physically taxing forms of athletic competition (eg, soccer). These results are discussed in light of potential factors that may have contributed to these differences.

Coalitional Physical Competition : Acute Salivary Steroid Hormone Responses among Juvenile Male Soccer Players in Hong Kong.

A large body of research links testosterone and cortisol to male-male competition. Yet, little work has explored acute steroid hormone responses to coalitional, physical competition during middle childhood. Here, we investigate testosterone, dehydroepiandrosterone (DHEA), androstenedione, and cortisol release among ethnically Chinese boys in Hong Kong (N = 102), aged 8-11 years, during a soccer match (n = 84) and an intrasquad soccer scrimmage (n = 81), with 63 participants competing in both treatments. The soccer match and intrasquad soccer scrimmage represented out-group and in-group treatments, respectively. Results revealed that testosterone showed no measurable change. DHEA increased during both treatments in the majority of participants and the degree of change had no relation to independent variables (e.g., performance, age, treatment, outcome) or covariate measures (Body Mass Index, Pubertal Development Scale). Most boys experienced androstenedione increases during match play, but no significant differences during the intrasquad soccer scrimmage competitions. The magnitude of change differed significantly between treatments and was positively associated with age. These latter findings suggest boys' androstenedione responses may be sensitive to competitor type (i.e., unknown competitors vs. peers). For most subjects, cortisol significantly increased during match play, decreased during the intrasquad soccer scrimmage, and differed significantly between treatments, suggesting each treatment promoted a different psychological state among competitors. Cortisol/DHEA molar ratio decreased during the intrasquad scrimmage, suggestive of a more relaxed mental state. These data shed new light on potential proximate mechanisms associated with coalitional competition among prepubescent boys, with relevance to adrenarche and life history theory.

Sex Hormone Metabolism and Threatened Abortion.

BACKGROUND The aim of this study was to evaluate changes in sex hormone metabolism in patients with threatened miscarriage. MATERIAL AND METHODS We recruited 73 women in early pregnancy (6-8 weeks of gestation) and divided them into the following 2 groups based on whether they had vaginal bleeding: group A (n=34), the threatened abortion group; and group B (n=39), the normal pregnancy group. Human chorionic gonadotrophin (hCG), estradiol (E2), progesterone (P4), and testosterone (T) serum levels were tested and sex hormone metabolites in the urine were detected using gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). As the control, data for sex hormones and their metabolites were obtained in normal women of childbearing age without pregnancy (group C: n=23). RESULTS E2 and T serum levels were lower in women with threatened miscarriage (group A). Estrone (E1), E2, estriol (E3), 16α-hydroxyestrone (16α-OHE1), 4-methoxyestrone (4-MeOE1), 2-hydroxyestradiol (2-OHE2), and 4-methoxyestradiol (4-MeOE2) levels were significantly lower in group A (P=0.001, 0.003, 0.009, 0.001, 0.012, 0.032, and 0.047, respectively.). Urine levels of dehydroepiandrosterone (DHEA), androstenedione (A2), and the metabolite of (A2) were also significantly lower in group A (P=0.007, 0.009, and 0.011, respectively). The 2-OHE1/E1, 4-OHE1/E1, 2-MeOE1/E1, and 2-MeOE2/E2 ratios were lower in group B, whereas the 2-OHE2/E2, 4-OHE2/E2, and 4-MeOE2/E2 ratios were dramatically lower in all pregnant women (groups A and B) than in group C. CONCLUSIONS Deficiency in DHEA and abnormal levels of sex hormone metabolites may cause a reduction in the activity of estrogens in women with threatened abortion. These alterations may result in bleeding during the first trimester of pregnancy.

Effectiveness of a Novel Qigong Meditative Movement Practice for Impaired Health in Flight Attendants Exposed to Second-Hand Cigarette Smoke.

This single-arm non-randomized pilot study explores an intervention to improve the health of flight attendants (FA) exposed to second-hand cigarette smoke prior to the smoking ban on commercial airlines. This group exhibits an unusual pattern of long-term pulmonary dysfunction. We report on Phase I of a two-phase clinical trial; the second Phase will be a randomized controlled trial testing digital delivery of the intervention. Subjects were recruited in the Northeastern US; testing and intervention were administered in 4 major cities. The intervention involved 12 h of training in Meditative Movement practices. Based on recent research on the effects of nicotine on fear learning, and the influence of the autonomic nervous system on immune function, our hypothesis was that this training would improve autonomic function and thus benefit a range of health measures. Primary outcomes were the 6-min walk test and blood levels of C-reactive protein. Pulmonary, cardiovascular, autonomic, and affective measures were also taken. Fourteen participants completed the training and post-testing. There was a 53% decrease in high sensitivity C-Reactive Protein (p ≤ 0.05), a 7% reduction in systolic blood pressure (p ≤ 0.05), a 13% increase in the 6-min walk test (p ≤ 0.005), and significant positive changes in several other outcomes. These results tend to confirm the hypothesized benefits of MM training for this population, and indicate that autonomic function may be important in the etiology and treatment of their symptoms. No adverse effects were reported. This trial is registered at ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT02612389/), and is supported by a grant from the Flight Attendant Medical Research Institute (FAMRI).

Associations between vitamin D levels and depressive symptoms in healthy young adult women.

There have been few studies of whether vitamin D insufficiency is linked with depression in healthy young women despite women׳s high rates of both problems. Female undergraduates (n=185) living in the Pacific Northwest during fall, winter, and spring academic terms completed the Center for Epidemiologic Studies Depression (CES-D) scale weekly for 4 weeks (W1-W5). We measured serum levels of vitamin D3 and C (ascorbate; as a control variable) in blood samples collected at W1 and W5. Vitamin D insufficiency (<30ng/mL) was common at W1 (42%) and W5 (46%), and rates of clinically significant depressive symptoms (CES-D≥16) were 34-42% at W1-W5. Lower W1 vitamin D3 predicted clinically significant depressive symptoms across W1-W5 (ß=-0.20, p<0.05), controlling for season, BMI, race/ethnicity, diet, exercise, and time outside. There was some evidence that lower levels of depressive symptoms in Fall participants (vs. Winter and Spring) were explained by their higher levels of vitamin D3. W1 depressive symptoms did not predict change in vitamin D3 levels from W1 to W5. Findings are consistent with a temporal association between low levels of vitamin D and clinically meaningful depressive symptoms. The preventive value of supplementation should be tested further.

Proinflammatory cytokines and DHEA-S in women with fibromyalgia: impact of psychological distress and menopausal status.

Though fibromyalgia is not traditionally considered an inflammatory disorder, evidence for elevated inflammatory processes has been noted in this disorder in multiple studies. Support for inflammatory markers in fibromyalgia has been somewhat equivocal to date, potentially due to inattention to salient patient characteristics that may affect inflammation, such as psychiatric distress and aging milestones like menopause. The current study examined the relationships between proinflammatory cytokines and hormone levels, pain intensity, and psychological distress in a sample of 34 premenopausal and postmenopausal women with fibromyalgia. Our results indicated significant relationships between interleukin-8 and ratings of pain catastrophizing (r=0.555, P<0.05), pain anxiety (r=0.559, P<0.05), and depression (r=0.551, P<0.05) for postmenopausal women but not premenopausal women (r,0.20 in all cases). Consistent with previous studies, ratios of interleukin-6 to interleukin-10 were significantly lower in individuals with greater levels of depressive symptoms (r=-0.239, P<0.05). Contrary to previous research, however, dehydroepiandrosterone sulfate did not correlate with pain intensity or psychological or biological variables. The results of the current study highlight the importance of psychological functioning and milestones of aging in the examination of inflammatory processes in fibromyalgia.

Percutaneous progesterone delivery via cream or gel application in postmenopausal women: a randomized cross-over study of progesterone levels in serum, whole blood, saliva, and capillary blood.

OBJECTIVE: This study aims to investigate the distribution of progesterone in venous whole blood, venous serum, fingertip capillary blood, and saliva after its topical application in both cream and gel formulations. METHODS: Ten postmenopausal women were randomized to receive 80 mg of progesterone cream or gel applied daily for 14 days, crossing over after a 14-day washout. On the last day of each treatment period, venous blood, fingertip capillary blood, and saliva were sampled frequently for 24 hours after the final application. RESULTS: After progesterone cream or gel application, serum progesterone levels rose gradually, reaching a peak at 9 and 8 hours, respectively; AUC(0-24) h was significantly higher with cream (12.39 vs 8.32 ng h mL(-1), P = 0.0391). Whole venous blood levels followed a pattern similar to that of serum but were considerably lower. Saliva progesterone showed a peak at 1 and 6 hours after cream and gel application, respectively, and C(max) was comparable with cream and gel. Saliva AUC(0-24) h was substantially higher than the corresponding area under the curve for serum or whole blood but did not differ significantly by delivery method (39.02 and 58.37 ng h mL(-1), P = 0.69). In capillary blood, C(max) was reached at the same time (8 h) and was similar with both formulations; AUC(0-24) h was also similar with both formulations (1,056 ng h mL(-1) for cream and 999 ng h mL(-1) for gel) but was dramatically higher than the corresponding areas under the curve for venous serum and whole blood. CONCLUSIONS: After application of topical progesterone, saliva and capillary blood levels are approximately 10-fold and 100-fold greater, respectively, than those seen in serum or whole blood. High capillary blood and saliva levels indicate high absorption and transport of progesterone to tissues. Reliance on serum levels of progesterone for monitoring topical dose could lead to underestimation of tissue levels and consequent overdose.

Iodine and creatinine testing in urine dried on filter paper.

Iodine deficiency is a world-wide health problem. A simple, convenient, and inexpensive method to monitor urine iodine levels would have enormous benefit in determining an individual's recent iodine intake or in identifying populations at risk for iodine deficiency or excess. Current methods used to monitor iodine levels require collection of a large volume of urine and its transport to a testing laboratory, both of which are inconvenient and impractical in parts of the world lacking refrigerated storage and transportation. To circumvent these limitations we developed and validated methods to collect and measure iodine and creatinine in urine dried on filter paper strips. We tested liquid urine and liquid-extracted dried urine for iodine and creatinine in a 96-well format using Sandell-Kolthoff and Jaffe reactions, respectively. Our modified dried urine iodine and creatinine assays correlated well with established liquid urine methods (iodine: R(2)=0.9483; creatinine: R(2)=0.9782). Results demonstrate that the dried urine iodine and creatinine assays are ideal for testing the iodine status of individuals and for wide scale application in iodine screening programs.

Assessment of Japanese iodine intake based on seaweed consumption in Japan: A literature-based analysis.

Japanese iodine intake from edible seaweeds is amongst the highest in the world. Predicting the type and amount of seaweed the Japanese consume is difficult due to day-to-day meal variation and dietary differences between generations and regions. In addition, iodine content varies considerably between seaweed species, with cooking and/or processing having an influence on iodine content. Due to all these factors, researchers frequently overestimate, or underestimate, Japanese iodine intake from seaweeds, which results in misleading and potentially dangerous diet and supplementation recommendations for people aiming to achieve the same health benefits seen by the Japanese. By combining information from dietary records, food surveys, urine iodine analysis (both spot and 24-hour samples) and seaweed iodine content, we estimate that the Japanese iodine intake--largely from seaweeds--averages 1,000-3,000 µg/day (1-3 mg/day).

Female social and sexual interest across the menstrual cycle: the roles of pain, sleep and hormones.

BACKGROUND: Although research suggests that socio-sexual behavior changes in conjunction with the menstrual cycle, several potential factors are rarely taken into consideration. We investigated the role of changing hormone concentrations on self-reported physical discomfort, sleep, exercise and socio-sexual interest in young, healthy women. METHODS: Salivary hormones (dehydroepiandrosterone sulfate-DHEAS, progesterone, cortisol, testosterone, estradiol and estriol) and socio-sexual variables were measured in 20 women taking oral contraceptives (OC group) and 20 not using OCs (control group). Outcome measures were adapted from questionnaires of menstrual cycle-related symptoms, physical activity, and interpersonal relations. Testing occurred during menstruation (T1), mid-cycle (T2), and during the luteal phase (T3). Changes in behavior were assessed across time points and between groups. Additionally, correlations between hormones and socio-behavioral characteristics were determined. RESULTS: Physical discomfort and sleep disturbances peaked at T1 for both groups. Exercise levels and overall socio-sexual interest did not change across the menstrual cycle for both groups combined. However, slight mid-cycle increases in general and physical attraction were noted among the control group, whereas the OC group experienced significantly greater socio-sexual interest across all phases compared to the control group. Associations with hormones differed by group and cycle phase. The estrogens were correlated with socio-sexual and physical variables at T1 and T3 in the control group; whereas progesterone, cortisol, and DHEAS were more closely associated with these variables in the OC group across test times. The direction of influence further varies by behavior, group, and time point. Among naturally cycling women, higher concentrations of estradiol and estriol are associated with lower attraction scores at T1 but higher scores at T3. Among OC users, DHEAS and progesterone exhibit opposing relationships with attraction scores at T1 and invert at T3. CONCLUSIONS: Data from this study show no change across the cycle in socio-sexual interest among healthy, reproductive age women but higher social and physical attraction among OC users. Furthermore, a broader range of hormones may be associated with attraction than previously thought. Such relationships differ by use of oral contraceptives, and may either reflect endogenous hormone modulation by OCs and/or self-selection of sexually active women to practice contraceptive techniques.

Postprandial insulin and triglycerides after different breakfast meal challenges: use of finger stick capillary dried blood spots to study postprandial dysmetabolism.

BACKGROUND: High levels of insulin and lipids following a meal are recognized risk factors for atherosclerosis. Monitoring such risk factors in the general population is hampered by the inconvenience of venipuncture blood collection, particularly for both premeal and postmeal analyses. This study examined insulin and triglyceride levels in dried blood spots (DBSs) collected after different breakfast meal challenges to assess the potential of this method for risk assessment. METHODS: Glucose levels were measured using a glucose meter, and insulin and triglycerides were determined in DBS samples collected from 19 healthy volunteers before and at four time points up to 2.5 h after consuming each of five typical breakfast meals varying in nutritional composition. RESULTS: At 2 h, glucose was within normal postprandial values (<140 mg/dl) for all meals; significantly lower glucose was seen after meal 2 (the lowest carbohydrate content) compared to the other meals. Insulin returned to normal fasting levels (<15 microIU/ml) in significantly more subjects (90%) after meal 2 and significantly fewer subjects (31%) after meal 4 (highest carbohydrate content) than the other meals. Triglycerides were elevated to a similar extent in all subjects, with no significant differences between meals; levels were still rising at 2.5 h. CONCLUSIONS: Subjects were able to collect blood spots with minimum disruption to their normal daily activities. Relative ease of collection, analyte stability in dried blood, and the close correlation with serum levels that we have previously demonstrated makes DBS a convenient and simple tool for assessing the individual impact of different diets on postprandial dysmetabolism.

A liquid chromatography/tandem mass spectrometry method for determination of 25-hydroxy vitamin D2 and 25-hydroxy vitamin D3 in dried blood spots: a potential adjunct to diabetes and cardiometabolic risk screening.

BACKGROUND: Now emerging as an important risk factor for type 1 diabetes, vitamin D deficiency is also associated with obesity, metabolic syndrome, and type 2 diabetes and has been identified as a potential cardiometabolic risk factor. A simple, accurate screening test for 25-hydroxy vitamin D [25(OH)D] deficiency is needed. We developed a liquid chromatography/tandem mass spectrometry assay for 25-hydroxy vitamin D(2) [25(OH)D(2)] and 25-hydroxy vitamin D(3) [25(OH)D(3)] in dried blood spots. METHOD: Blood spots were collected by finger stick simultaneously with serum samples obtained by venipuncture from healthy volunteers. Disks punched from the dried blood spots were sonicated with an internal standard solution of deuterated 25(OH)D(3) (26,26,26,27,27,27-d(6)). Methanol was added to precipitate proteins prior to extraction with hexane. The extracted samples were dried and reconstituted in 50:50 methanol:H(2)O before injection into a Varian 320-MS TQ mass spectrometer. RESULTS: BLOOD SPOT ASSAY PRECISION WAS GOOD OVER THE REPORTABLE RANGE: interassay coefficients of variation were 13, 13, and 11% at concentrations of 14, 26, and 81 ng/ml, respectively, for 25-hydroxy vitamin D(3) and 12% at 23 ng/ml for 25(OH)D(2). The 25(OH)D(3) assay was linear from 3.5 to 75 ng/ml (R > 0.99). Blood spot and serum values showed excellent correlation for 25(OH)D(2) (R=0.90, n=54) and 25(OH)D(3) (R=0.91, n=83). CONCLUSIONS: This blood spot assay for 25(OH)D(2) and 25(OH)D(3) provides a convenient and cost-effective alternative to serum assays and can be automated. This may be valuable in large-scale screening for risk of type 1 diabetes, for cardiometabolic risk screening, and for monitoring vitamin D supplementation.