Low free 25-hydroxyvitamin D and high vitamin D binding protein and parathyroid hormone in obese Caucasians. A complex association with bone?

Association of vitamin D levels with anthropometric and adiposity indicators across all age groups: a systematic review of epidemiologic studies

Objectives

It has not been established whether vitamin D deficiency is associated with anthropometric state; therefore, this systematic review examined the relationship between serum vitamin D levels with anthropometrics and adiposity across different ages.

Methods

Studies that examined vitamin D deficiency with adiposity measures in different age groups were searched in the PubMed, Scopus, Embase, and Google Scholar databases until November 2023. Two investigators independently reviewed titles and abstracts, examined full-text articles, extracted data, and rated the quality in accordance with the Newcastle-Ottawa criteria.

Results

Seventy-two studies, with a total of 59,430 subjects, were included. Of these studies, 27 cross-sectional studies and one longitudinal study (with 25,615 participants) evaluated the possible link between 25(OH)D serum concentrations and anthropometric/adiposity indices in the pediatric population. Forty-two cross-sectional studies and two cohort investigations (with 33,815 participants) investigated the relationship between serum 25(OH)D levels and adiposity measures in adults and/or the elderly population. There is evidence supporting links between vitamin D deficiency and obesity, and revealed an inverse association between vitamin D and adiposity indicators, specifically in female subjects. However, the effects of several confounding factors should also be considered.

Conclusion

Most published studies, most of which were cross-sectional, reported a negative association between vitamin D and female adiposity indicators. Therefore, serum vitamin D levels should be monitored in overweight/obese individuals.

Vitamin D deficiency: a potential risk factor for cancer in obesity?

Obesity is considered an abnormal or excessive accumulation of adipose tissue, due to a prolonged positive energy balance that arises when energy intake is greater than energy expenditure, leading to an increased risk for the individual health and for the development of metabolic chronic diseases including several different types of cancer. Vitamin D deficiency is a metabolic alteration, which is often associated with the obesity condition. Vitamin D is a liposoluble vitamin, which plays a pivotal role in calcium-phosphate metabolism but extraskeletal effects have also been described. Among these, it plays an important role also in adipocyte physiology and glucose metabolism, typically dysregulated in subjects affected by obesity. Moreover, it is now recognized that Vitamin D also influences the processes of cell proliferation, differentiation, adhesion potentially leading to carcinogenesis. Indeed, data indicate a potential link between vitamin D levels and cancer, and higher vitamin D concentrations have been associated with a lower risk of developing different kinds of tumors, including breast, colon, lymphoma, lung, and prostate cancers. Thus, this review will revise the literature regarding this issue investigating and highlighting the potential mechanism of action, which might lead to new therapeutical options.

Effect of physical activity and BMI SDS on bone metabolism in children and adolescents

OBJECTIVE

Children with obesity are known to have reduced bone density and are at a higher risk for fractures. This may be caused by decreased physical activity or a metabolic phenomenon. In this study, we evaluated associations of physical activity with bone metabolism in children and adolescents with and without obesity.

METHODS

Results from 574 visits of 397 subjects, 191 girls and 206 boys aged five to 18 years (mean: 11.7 ± 2.8) representing 180 children with (mean BMI SDS 2.5 ± 0.4) and 217 without obesity (mean BMI SDS 0.2 ± 1.0) from the LIFE Child study, a population-based cohort of children/adolescents with normal weight and with obesity were analyzed for the impact of their daily physical activity (MET/day, SenseWear Accelerometer) on serum SDS levels for bone formation (alkaline phosphatase, osteocalcin, procollagen type I N propeptide [P1NP]), bone resorption (beta-crosslaps), and calcium homeostasis (parathormone, OH-25-vitamin D) by a linear regression model adjusted for gender- and age-based differences.

RESULTS

For male subjects, BMI SDS significantly influenced the association of physical activity to PTH, vitamin D, and beta-crosslaps SDS levels. A higher physical activity was accompanied by increased PTH but decreased vitamin D SDS levels in children with normal weight. In males with obesity, all levels remained unaltered. In females, BMI SDS significantly impacted the association of physical activity to PTH, vitamin D, P1NP, beta-crosslaps, and osteocalcin SDS levels. In females with obesity, higher physical activity was related to higher SDS levels of vitamin D, P1NP, and beta-crosslaps. In contrast, in normal weight females, only PTH SDS was higher.

CONCLUSIONS

The effect of daily physical activity on bone metabolic markers and calciotropic hormones depends significantly on gender and BMI SDS. However, higher levels of physical activity were associated with increased bone turnover for female subjects with obesity only. Thus, motivating especially girls with obesity to be physically active may help improve their bone health.

Is Bioavailable Vitamin D Better Than Total Vitamin D to Evaluate Vitamin D Status in Obese Children?

INTRODUCTION

Free hormones are biologically more active in target tissues. Thus, measurement of vitamin D taking into account bioavailability and free vitamin D may be preferable, especially when evidence is contradictory, as in obese children. In order to assess bioavailablity and free vitamin D, using a previously reported formula, vitamin D-binding protein (VDBP) level was measured and VDBP polymorphisms were also evaluated because of variations in binding affinity.

METHODS

Eighty-four obese and 78 healthy children were included. Anthropometry, calcium, phosphorus, alkaline-phosphatase, parathyroid hormone (PTH), 25 hydroxyvitamin D [25(OH)D], bioavailable-free vitamin D, and VDBP concentration and polymorphism were evaluated in the whole group.

RESULTS

Obese girls had significantly higher PTH than normal weight girls (p=0.001). Regardless of gender, obese children had significantly higher concentrations of VDBP (p=0.008) and PTH (p=0.002). When samples taken in winter were analyzed, PTH and VDBP were found to be higher and bioavailable and free vitamin D lower in the obese group. There was no difference in terms of total vitamin D between groups during the winter season.

CONCLUSION

While total, free, and bioavailable vitamin D in the obese group was similar to the control group in autumn, free and bioavailable vitamin D in the winter was lower in the obese than the control group. In addition, PTH was higher in the obese group in both autumn and winter. Therefore, more research is needed to evaluate the variability of free and bioavailable vitamin D according to body habitus, season and the effect any differences may have.

Association between obesity and risk of fracture, bone mineral density and bone quality in adults: A systematic review and meta-analysis

BACKGROUND

The association between obesity and fracture risk may be skeletal site- and sex-specific but results among studies are inconsistent. Whilst several studies reported higher bone mineral density (BMD) in patients with obesity, altered bone quality could be a major determinant of bone fragility in this population.

OBJECTIVES

This systematic review and meta-analysis aimed to compare, in men, premenopausal women and postmenopausal women with obesity vs. individuals without obesity: 1) the incidence of fractures overall and by site; 2) BMD; and 3) bone quality parameters (circulating bone turnover markers and bone microarchitecture and strength by advanced imaging techniques).

DATA SOURCES

PubMed (MEDLINE), EMBASE, Cochrane Library and Web of Science were searched from inception of databases until the 13th of January 2021.

DATA SYNTHESIS

Each outcome was stratified by sex and menopausal status in women. The meta-analysis was performed using a random-effect model with inverse-variance method. The risks of hip and wrist fracture were reduced by 25% (n = 8: RR = 0.75, 95% CI: 0.62, 0.91, P = 0.003, I2 = 95%) and 15% (n = 2 studies: RR = 0.85, 95% CI: 0.81, 0.88), respectively, while ankle fracture risk was increased by 60% (n = 2 studies: RR = 1.60, 95% CI: 1.52, 1.68) in postmenopausal women with obesity compared with those without obesity. In men with obesity, hip fracture risk was decreased by 41% (n = 5 studies: RR = 0.59, 95% CI: 0.44, 0.79). Obesity was associated with increased BMD, better bone microarchitecture and strength, and generally lower or unchanged circulating bone resorption, formation and osteocyte markers. However, heterogeneity among studies was high for most outcomes, and overall quality of evidence was very low to low for all outcomes.

CONCLUSIONS

This meta-analysis highlights areas for future research including the need for site-specific fracture studies, especially in men and premenopausal women, and studies comparing bone microarchitecture between individuals with and without obesity.

SYSTEMATIC REVIEW REGISTRATION NUMBER

CRD42020159189.

Multiplex LC-MS/MS for simultaneous determination of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D3, albumin, and vitamin D-binding protein with its isoforms: One-step estimation of bioavailable vitamin D and vitamin D metabolite ratio

Bioavailable vitamin D and vitamin D metabolite ratio (VMR) have emerged as potential novel vitamin D markers. We developed a multiplex liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine all elements necessary for the calculation of bioavailable vitamin D and VMR, including 25-hydroxyvitamin D [25-(OH)D] and 24,25-dihydroxyvitamin D₃ [24,25-(OH)₂D₃], VDBP and its isoforms, and albumin. Following separate reactions of hexane extraction and trypsin digestion, serum samples were analyzed using LC-MS/MS to measure 25-(OH)D₃, 25-(OH)D₂, 24,25-(OH)₂D₃, VDBP and its isoforms, and albumin. Analytical performances were assessed. Korean (n = 229), Arab (n = 98), White (n = 99) and Black American (n = 99) samples were analyzed. Bioavailable vitamin D and VMR were calculated. All target molecules were clearly separated and accurately quantified by LC-MS/MS. Analytical performances, including imprecision, accuracy, ion suppression, limit of quantification, linearity, and comparison with existing methods were within acceptable levels. The allele frequencies of VDBP isoforms in various races resulted similar to previously known values. The levels of bioavailable vitamin D were highest in White Americans and lowest in Black Americans. We have successfully developed a multiplex LC-MS/MS-based assay method that can simultaneously perform the measurement of all parameters needed to calculate bioavailable vitamin D and VMR. Our devised method was robust and reliable in terms of analytical performances and could be applied to routine clinical samples in the future to more accurately assess vitamin D status.

Total, Bioavailable, and Free 25(OH)D Relationship with Indices of Bone Health in Elderly: A Randomized Controlled Trial

CONTEXT

Questions regarding the superiority of free and bioavailable 25-hydroxyvitamin D [25(OH)D] in predicting health outcomes remain unresolved.

OBJECTIVE

This study investigates the impact of vitamin D variables-total, bioavailable, or free 25(OH)D-on indices of bone and mineral metabolism, at baseline and in response to 2 vitamin D doses.

DESIGN

Our objectives are implemented as exploratory analyses on data collected in a 1-year, double-blind, randomized controlled trial completed in July 2014.

SETTING

Participants were recruited from 3 major hospitals in an ambulatory setting.

PARTICIPANTS

Participants were >65 years of age, overweight, and had a baseline serum 25(OH)D between 10 and 30 ng/mL. A total of 221 participants completed the study.

INTERVENTION

Subjects were randomized to receive calcium and oral vitamin D3 (600 IU/day or 3750 IU/day) supplementation.

RESULTS

Participants who received the higher vitamin D dose had levels that were 1.3- to 1.4-fold higher than those taking the lower dose, for all variables (P value < 0.001). Serum values of bioavailable and free 25(OH)D were associated with total 25(OH)D, with r values of 0.942 and 0.943, respectively (P value < 0.001). Parathyroid hormone (PTH) was negatively associated with all vitamin D variables, with correlation coefficients ranging from -0.22 to -0.25, while calcium and bone turnover markers (carboxy-terminal collagen crosslinks and osteocalcin) did not. Only total 25(OH)D had a positive relationship with % change bone mineral density (BMD) at the femoral neck at 12 months, while only free and bioavailable 25(OH) had a positive relationship with % change total body BMD at 12 months.

CONCLUSION

Calculated free and bioavailable 25(OH)D do not appear to be superior to total 25(OH)D in predicting indices of bone health in an elderly population.

Free and Bioavailable Fractions of Vitamin D: Association with Maternal Characteristics in Brazilian Pregnant Women

Normal pregnancy is characterized by many changes in vitamin D metabolism, challenging the assessment of vitamin D status based exclusively on serum total 25-hydroxyvitamin D (25(OH)D). We hypothesized that measuring free and bioavailable fractions contributes to a better vitamin D status assessment in late pregnancy. Our aim was to evaluate a broad set of biomarkers of vitamin D status in Brazilian women in the third trimester of pregnancy. This cross-sectional study was conducted in women (n = 123, 18-44 y, 27-41 wk gestation) attended in a public maternity in Rio de Janeiro (2016-2018). Biomarkers included serum concentrations of total 25(OH)D3, parathyroid hormone (PTH), vitamin D-binding protein (DBP), and free and bioavailable fractions of 25(OH)D3. Vitamin D insufficiency (<50 nmol/L) was prevalent in 47.9% of the pregnant women. Serum 25(OH)D3 was inversely associated with the gestational week (β = -0.71, 95% confidence interval (CI): -1.31 to -0.16) and season, being lower in autumn (β = -9.90, 95% CI: -16.14 to -3.64) and winter (β = -16.74, 95%CI: -23.13 to -10.34). Concentrations of DBP, and free and bioavailable 25(OH)D3 were also inversely associated with winter months (P < 0.05). DBP was directly associated with prepregnancy BMI (β = 5.84, 95% CI: 0.62 to 11.06). The recognized season-effect on total 25(OH)D3 appeared to also occur on free and bioavailable fractions. Although advanced gestational age was associated with lower total 25(OH)D3, our results suggest an adaptive mechanism responsible for maintaining free fraction during the 3rd trimester. We also suggest that starting pregnancy in obese condition may have an impact on vitamin D bioavailability, which deserves further investigation.

Vitamin D levels, prediabetes risk and hemoglobin A1c levels in young non-diabetic Saudi women

AIMS/INTRODUCTION

Vitamin D levels are negatively correlated with prediabetes risk and hemoglobin A1c levels in individuals with prediabetes. The data are, however, scarce and inconsistent among different populations. We aimed to assess the association of vitamin D with prediabetes risk and hemoglobin A1c levels in young Saudi women with normoglycemia and prediabetes.

MATERIALS AND METHODS

We analyzed the data of individuals without diabetes (without diabetes history and hemoglobin A1c <6.4%) from the Princess Nourah bint Abdulrahman University's non-communicable diseases student registry. Demographic data, anthropometric and blood pressure measurements, and hemoglobin A1c and vitamin D results were retrieved and analyzed.

RESULTS

In total, 345 participants were included in the analysis. The prediabetes status showed no association with vitamin D levels, but it was significantly associated with the participants' weight and body mass index. Additionally, there was no correlation between the levels of vitamin D and hemoglobin A1c across the whole population, even after correction for body mass index. However, in the body mass index subgroups, when individuals with potentially harmful levels of vitamin D (>125 nmol/L) were excluded, a positive association was detected between vitamin D and hemoglobin A1c levels in the underweight individuals. Hemoglobin A1c values showed a positive correlation only with bodyweight and body mass index.

CONCLUSIONS

Vitamin D levels did not predict prediabetes status and showed no correlation with hemoglobin A1c levels in this population. Vitamin D levels' effect on the risk of prediabetes might be small compared with other well-established risk factors, such as obesity.

Visceral Fat Is a Negative Determinant of Bone Health in Obese Postmenopausal Women

The protective effect of obesity on bone health has been challenged by studies that link visceral adiposity to poor bone microarchitecture in young obese men and women. In postmenopausal women, the role of visceral adipose tissue (VAT) on bone turnover markers (BTMs) has not been investigated. The aim was to investigate the impact of VAT on BTMs, total bone mineral density (BMD), vitamin D metabolites and parathyroid levels (1-84 PTH) levels in postmenopausal women. A total of 76 lean and overweight women (without osteoporosis) underwent VAT measurements by dual-energy X-ray absorptiometry (iDXA). Blood samples were analyzed for serum C-terminal telopeptide of type 1 collagen (CTX-1), osteocalcin, bone-specific alkaline phosphatase (bone ALP), 1–84 PTH and vitamin D (25 hydroxyvitamin D, 25(OH)D) levels. VAT volumes ranged from 91 to 3392 cm³ and body mass index (BMI) ranged from 18.3 to 53.9 kg/m². Women in the highest VAT quartile had significantly lower CTX-1, 25(OH)D, osteocalcin and the highest BMD (p < 0.05, for all). While VAT positively associated with BMD, after controlling for BMI, VAT was a negative predictor of BMD (β = 0.368, p < 0.05). VAT was an independent negative predictor of CTX-1 (β = −0.263, p < 0.05) and osteocalcin levels (β = −0.277, p < 0.05). Among all measures of adiposity, VAT was the strongest independent determinant of BMD and BTMs. In clinical settings, VAT, and not BMI, may be a sensitive predictor of bone health in obese women.

Significance of Vitamin D Binding Protein in Assessing Vitamin D Status Among Under-Five Children

Despite ample sunshine, 50-90% Indian children have Vitamin D deficiency (VDD). This enigma of widespread VDD needs exploration especially among under-fives as physiological variations in Vitamin D Binding Protein (VDBP) levels could be potential confounders in the interpretation of total 25-hydroxyvitamin D [25(OH)D]. However, there is scarce information about relevance of VDBP levels in under-five age group. We therefore, explored association of VDBP levels among 1-5 year old children with VDD. Serum levels of 25(OH)D, VDBP, calcium, parathyroid hormone (PTH) and alkaline phosphatase were estimated in 210 apparently healthy children in the age group of 1-5 years. VDD was defined as serum 25(OH)D levels < 20 ng/ml as per the IOM classification. VDBP levels were classified as low if levels were < 168 μg/ml as per the kit. The prevalence of VDD was 79.5% (n = 167) and VDBP levels were low in 48.6% (n = 102) of children. 25(OH)D levels correlated positively with VDBP (r = 0.298, p = 0.0001). A significant number of children (52.7%) with VDD had low VDBP (p = 0.015). and despite adequate sun exposure, 43% of children showed VDD and 56.6% had low VDPB levels. The low VDBP levels largely explain low 25OHD levels without necessarily implying VDD. It may add a new dimension for better understanding of widespread VDD among under-five children. It thus, points towards the need for redefining cut offs and complete evaluation of vitamin D status among under-fives including VDBP.

Peripheral quantitative computed tomography (pQCT)-based finite element analysis provides enhanced diagnostic performance in identifying non-vertebral fracture patients compared with dual-energy X-ray absorptiometry

Due to limitations of the predominant clinical method for diagnosing osteoporosis, an engineering model based on a dedicated CT scanner for bone density and structure was applied in fracture patients and controls. Improved diagnostic performance was observed, which supports its potential use in future research and clinical practice.

INTRODUCTION

Dual-energy X-ray absorptiometry (DXA), the predominant clinical method for diagnosing osteoporosis, has limitations in identifying individuals with increased fracture risk. Peripheral quantitative computed tomography (pQCT) provides additional information and can be used to generate finite element (FE) models from which bone strength properties can be estimated. We investigated the ability of pQCT-FE properties to distinguish peripheral low-trauma fracture patients from healthy controls, by comparison with DXA and standard pQCT.

METHODS

One hundred and eight fracture patients (77 females aged 67.7 ± 7.9 years, 31 males aged 69.7 ± 8.9 years) were recruited from a hospital fracture liaison service. One hundred and twenty healthy community controls (85 females aged 69.8 ± 8.5 years, 35 males aged 68.9 ± 7.2 years) were recruited.

RESULTS

Significant differences between groups were observed in pQCT-FE properties, especially at the 4% tibia site. Fracture odds increased most per standard deviation decrease in pQCT-FE at this location [shear stiffness estimate, k_shear, in females, OR = 10.34, 95% CI (1.91, 43.98); bending stiffness estimate, k_bend, in males, OR = 8.32, 95% CI (4.15, 33.84)]. Area under the receiver operating characteristics curve (AUROC) was observed to be highest with pQCT-FE properties at 4% the tibia site. In females, this was 0.83 for the pQCT-FE variable k_shear, compared with 0.72 for DXA total hip bone density (TH aBMD) and 0.76 for pQCT tibia trabecular density (Trb vBMD); in males, this was 0.81 for the pQCT-FE variable k_bend at the 4% tibia site, compared with 0.62 for TH aBMD and 0.71 for Trb vBMD. There were significant differences in AUROC between DXA and pQCT-FE variables in both females (p = 0.02) and males (p = 0.03), while no difference was observed in AUROC between primary pQCT and pQCT-FE variables.

CONCLUSIONS

pQCT-FE modeling can provide enhanced diagnostic performance compared with DXA and, given its moderate cost, may be useful in clinical settings.

Lower serum 25-hydroxyvitamin D3 concentration is associated with higher pain and disability in subjects with low back pain: a case-control study

Objectives

Low back pain (LBP) is a common medical problem worldwide. The aim of this study is to evaluate the association between serum concentration of 25-hydroxivitamin D3 and functional disability in patients suffering from LBP in a sample of Azeri middle-aged subjects, North West of Iran.

Results

In this case–control study, 63 eligible patients with LBP and 55 healthy subjects enrolled in the study. Peripheral venous blood was taken for evaluating the serum concentration of 25-hydroxivitamin D3. We recognized factors related with LBP by multiple regression analyses. The average serum 25-hydroxivitamin D3 concentration in case group was significantly lower than that of the matched controlled group (26.25 ± 15.95 vs. 34.20 ± 14.92, p-value < 0.01 respectively). Subjects with vitamin D deficiency or insufficiency were more likely to exhibit LBP than subjects with normal serum 25-hydroxivitamin D3 concentration [(OR = 2.388, 95% CI (1.114 to 5.119)]. According to the partial correlation analysis, there was a reverse correlation between serum 25-hydroxivitamin D3 concentration with functional disability measured by Modified Oswestry Questionnaire (r = − 0.307, p = 0.017) and also with pain intensity according to Visual Analogue Scale (VAS) score (r = − 0.268, p = 0.040) whilst adjusting for age, sex and body mass index (BMI).

Associations of Serum 25-Hydroxyvitamin D with Physical Performance and Bone Health in Overweight and Obese Older Adults

Low vitamin D status commonly accompanies obesity, and both vitamin D deficiency and obesity have been associated with falls and fracture risk in older adults. We aimed to determine the associations of serum 25-hydroxyvitamin D (25(OH)D) concentrations with physical performance and bone health in community-dwelling, overweight and obese older men and women. Serum 25(OH)D concentrations were measured in 84 participants with body mass index ≥25 kg/m² (mean ± SD age 62.4 ± 7.9 years; 55% women). Physical function was determined by short physical performance battery, hand grip and quadriceps strength, and stair climb power tests. Body composition and bone structure were assessed by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively. Mean ± SD 25(OH)D was 49.6 ± 17.7 nmol/L, and 50% of participants had low 25(OH)D (<50 nmol/L) levels. 25(OH)D concentrations were positively associated with quadricep strength and stair climb power in women (B = 0.15; 95% CI 0.02–0.27 kg and B = 1.07; 95% CI 0.12–2.03 W, respectively) but not in men. There were no associations between 25(OH)D and bone parameters in either sex after multivariable adjustment (all p > 0.05). Lower 25(OH)D concentrations are associated with poorer quadricep strength and muscle power in overweight and obese older women but not men.

Evolving Role of Vitamin D in Immune-Mediated Disease and Its Implications in Autoimmune Hepatitis

Vitamin D has immunomodulatory, anti-inflammatory, antioxidant, and anti-fibrotic actions that may impact on the occurrence and outcome of immune-mediated disease. The goals of this review are to describe the nature of these expanded roles, examine the implications of vitamin D deficiency in autoimmune hepatitis, and identify opportunities for future investigation. Abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Vitamin D receptors are expressed on the principal cell populations involved in the innate and adaptive immune responses. Macrophages and dendritic cells can produce 1,25-dihydroxyvitamin D within the microenvironment. This active form of vitamin D can inhibit immune cell proliferation, promote an anti-inflammatory cytokine profile, expand regulatory T cells, enhance glucocorticoid actions, increase glutathione production, and inhibit hepatic stellate cells. Vitamin D deficiency has been commonly present in patients with immune-mediated liver and non-liver diseases, and it has been associated with histological severity, advanced hepatic fibrosis, and non-response to conventional glucocorticoid therapy in autoimmune hepatitis. Vitamin D analogues with high potency, low calcemic effects, and independence from hepatic hydroxylation are possible interventions. In conclusion, vitamin D has properties that could ameliorate immune-mediated disease, and vitamin D deficiency has been a common finding in immune-mediated liver and non-liver diseases, including autoimmune hepatitis. Loss of vitamin D-dependent homeostatic mechanisms may promote disease progression. Vitamin D analogues that are independent of hepatic hydroxylation constitute an investigational opportunity to supplement current management of autoimmune hepatitis.

Cigarette Smoke During Breastfeeding in Rats Changes Glucocorticoid and Vitamin D Status in Obese Adult Offspring

Maternal smoking increases obesogenesis in the progeny. Obesity is associated with several hormonal dysfunctions. In a rat model of postnatal tobacco smoke exposure, we previously reported increased central fat depot and disruption of some hormonal systems in the adult offspring. As both glucocorticoids and vitamin D alter lipogenesis and adipogenesis, here we evaluated the metabolism of these two hormones in visceral adipose tissue (VAT) and liver by Western blotting, and possible associations with lipogenesis biomarkers in adult rats that were exposed to tobacco smoke during their suckling period. At postnatal day (PN) 3, dams and offspring of both sexes were exposed (S group) or not (C group) to tobacco smoke, 4 × 1 h/day. At PN180, corticosteronemia was lower in S male and higher in S female offspring, without alterations in peripheral glucocorticoid metabolism and receptor. Adrenal ACTH receptor (MC2R) was higher in both sexes of S group. Despite unchanged serum vitamin D, liver 25-hydroxylase was higher in both sexes of S group. Male S offspring had higher 1α-hydroxylase, acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS) in VAT. Both sexes showed increased ACC protein content and reduced sirtuin mRNA in liver. Male S offspring had lower liver peroxisome proliferator-activated receptor-α. Tobacco exposure during lactation induced abdominal obesity in both sexes via distinct mechanisms. Males and females seem to develop HPA-axis dysfunction instead of changes in glucocorticoid metabolism and action. Lipogenesis in VAT and liver, as well as vitamin D status, are more influenced by postnatal smoke exposure in male than in female adult rat offspring.