Related by context. All words. (Click for frequent words.) 82 gum disease 80 periodontitis 70 periodontal 68 periodontal diseases 68 gingivitis 66 periodontal gum disease 65 Periodontal disease 63 NAFLD 63 Periodontitis 63 dental caries 62 periodontal infection 62 dental cavities 62 tooth decay 61 chronic periodontitis 61 skeletal fluorosis 61 fatty liver disease 60 atherosclerosis 60 colorectal polyps 60 cardiovascular disease 59 dental decay 59 atopic dermatitis 59 metabolic syndrome 59 tartar buildup 59 insulin resistance 59 AAT deficiency 58 subclinical atherosclerosis 58 preeclampsia 58 oral hygiene 58 eczema 58 folate deficiency 58 subclinical hypothyroidism 58 reflux disease 58 vitamin D deficiency 58 obstructive sleep apnea 58 inflammatory bowel disease 58 sleep disordered breathing 57 caries 57 polycystic ovary syndrome PCOS 57 diabetic retinopathy 57 preterm delivery 57 elevated CRP 57 severe periodontitis 57 modifiable risk 57 periodontal infections 57 gallstone disease 57 atherosclerotic disease 57 nonmelanoma skin cancer 56 GERD 56 T1DM 56 receding gums 56 chronic rhinosinusitis 56 Vitamin D insufficiency 56 vascular disease 56 bruxism 56 gingival recession 56 thyroid dysfunction 56 H. pylori infection 56 coronary heart 56 diabetes mellitus 56 lichen planus 56 polycystic ovary syndrome 56 bacterial vaginosis 56 heart disease 56 psoriasis 55 dental fluorosis 55 postmenopausal breast cancer 55 gestational diabetes 55 endothelial dysfunction 55 urolithiasis 55 liver fibrosis 55 intestinal polyps 55 knee osteoarthritis 55 colorectal tumors 55 fibrosis 55 Helicobacter pylori infection 55 oxidative stress 55 subclinical hyperthyroidism 55 fluorosis 55 VUR 55 venous thrombosis 55 coronary artery disease 55 colorectal cancer CRC 55 osteoporosis 55 airway hyperresponsiveness 55 SIBO 54 colorectal cancer 54 dentinal hypersensitivity 54 COPD 54 bowel cancers 54 preterm birth 54 thyroid function 54 H. pylori 54 HBV infection 54 periodontal bacteria 54 disease NAFLD 54 retinopathy 54 postoperative pulmonary 54 subclinical 54 enamel defects 54 colorectal adenoma 54 carotid stenosis 54 nicotine dependence 54 cardiovascular disease CVD 54 pyloric stenosis 54 gingival bleeding 54 colorectal adenomas 54 CMV infection 54 CP CPPS 54 Gingivitis 54 atopic disease 54 bone resorption 54 systemic inflammation 54 endometrial hyperplasia 54 bowel polyps 54 gestational diabetes mellitus 54 basal cell nevus syndrome 54 cavities gingivitis 54 root caries 54 carotid plaque 54 proliferative diabetic retinopathy 54 microalbuminuria 54 metabolic disturbances 54 Sjögren syndrome 53 albuminuria 53 C reactive protein 53 adrenal function 53 chronic prostatitis 53 mitochondrial mutations 53 hypertension 53 untreated celiac disease 53 atopy 53 serum phosphate 53 bacterial overgrowth 53 Sjogren syndrome 53 hyperparathyroidism 53 oropharyngeal cancers 53 coronary disease 53 pharyngeal cancers 53 cardiovascular mortality 53 familial adenomatous polyposis 53 genetic susceptibility 53 disc degeneration 53 HPV infection 53 venous blood clots 53 dentin hypersensitivity 53 coronary calcification 53 carotid atherosclerosis 53 glucose intolerance 53 pre cancerous growths 53 basal cell carcinomas 53 Vitamin B# deficiency 53 androgenetic alopecia 53 chronic pancreatitis 53 folate intake 53 proliferative retinopathy 53 Periodontology 53 coronary artery calcium 53 herpes infection 53 hypospadias 53 adenomatous polyps 53 benign breast 53 oxidized phospholipids 53 breast abscesses 53 renal dysfunction 53 cardio metabolic 53 Onychomycosis 53 chlamydia infection 53 ovarian hormones 53 asthma rhinitis 53 colon polyps 53 recurrent miscarriages 52 atherosclerotic lesions 52 atopic 52 cryptorchidism 52 tooth decay gum 52 pre cancerous lesions 52 parkinsonism 52 H pylori 52 thoracic aortic aneurysm 52 folic acid deficiency 52 calcium supplementation 52 underactive thyroid 52 POAG 52 caries cavities 52 Tooth decay 52 cervical lesions 52 familial pancreatic cancer 52 endometrial cancer 52 osteoarthritis 52 hydroxyvitamin D levels 52 Hashimoto thyroiditis 52 nonmelanoma skin cancers 52 benign growths 52 hyperphosphatemia 52 bacteriuria 52 laryngeal cancer 52 diabetes 52 HNSCC 52 cognitive decline 52 iron overload 52 varicocele 52 genital ulcers 52 pre eclampsia 52 TMJ disorders 52 recurrent infections 52 Vitamin D deficiency 52 cataract formation 52 salivary flow 52 recurrent wheezing 52 acne vulgaris 52 post thrombotic syndrome 52 photoaging 52 hereditary predisposition 52 kidney dysfunction 52 premenopausal breast cancer 52 nasal obstruction 52 pharyngeal cancer 52 colorectal neoplasia 52 intravenous bisphosphonates 52 diabetes mellitus DM 52 microvascular disease 52 atopic eczema 52 polyp recurrence 52 urinary symptoms 52 atherogenic dyslipidemia 52 vitamin D insufficiency 52 photodamaged skin 52 esophageal cancers 52 oral clefts 52 airway inflammation 52 bleeding gums 52 overactive bladder symptoms 52 adenoma 52 endotoxemia 52 uric acid levels 52 chronic inflammation 52 arterial plaque 52 vaginal infections 52 enterovirus infection 52 elevated triglyceride levels 52 metabolic abnormality 52 neurodevelopmental outcomes 51 gouty arthritis 51 ischemic stroke 51 acne breakouts 51 abdominal obesity 51 facial wrinkling 51 diverticulosis 51 Dental caries 51 cardiovascular disease hypertension 51 renal scarring 51 knee OA 51 atherosclerotic CVD 51 oxidative damage 51 RSV infections 51 gastric cancer 51 hypercholesterolemia 51 microvascular complications 51 adiponectin levels 51 BRCA1 mutations 51 prediabetes 51 Candida infection 51 oral malodor 51 artery calcification 51 otitis media 51 scalp psoriasis 51 developmental abnormalities 51 ulceration 51 dietary calcium 51 fragility fractures 51 Barrett esophagus 51 hyperthyroidism 51 jaw osteonecrosis 51 hypovitaminosis D 51 hepatic steatosis 51 facial clefts 51 phthalate exposure 51 pattern baldness 51 oesophageal 51 chronic heartburn 51 Alzheimers disease 51 calcium deficiency 51 AUDs 51 chronic hepatitis 51 varicoceles 51 retinal detachment 51 neural tube defect 51 endometrial cancers 51 chronic otitis media 51 oropharyngeal cancer 51 postoperative infection 51 Chlamydia pneumoniae 51 cardio vascular disease 51 adenomas 51 MetS 51 seborrheic dermatitis 51 elevated homocysteine 51 squamous cell carcinomas 51 periodontal pathogens 51 fructose intolerance 51 lobular breast cancer 51 C Reactive Protein 51 atherothrombosis 51 UTIs 51 breast cancer metastasis 51 hyperhidrosis 51 macrovascular disease 51 macrovascular 51 precocious puberty 51 serum cholesterol 51 preterm deliveries 51 irregular menstrual cycles 51 elevated uric acid 51 renovascular hypertension 51 macrovascular complications 51 xerostomia 51 canker sores 51 genetic variants 51 systemic lupus erythematosus SLE 51 prostate carcinogenesis 51 impaired glucose tolerance 51 nonalcoholic steatohepatitis 51 abnormal lipids 51 fecal incontinence 51 cardioembolic stroke 51 estrogen deficiency 51 type 1diabetes 51 abdominal adiposity 50 pre cancerous polyps 50 subfertility 50 airflow obstruction 50 type2 diabetes 50 polycystic ovarian syndrome PCOS 50 enamel fluorosis 50 periodontal tissue 50 osteoporotic 50 epigenetic changes 50 osteoporotic fracture 50 obesity 50 L. reuteri 50 genetic determinants 50 osteoporotic fractures 50 OGG1 50 glycemic diet 50 alveolar bone loss 50 hirsutism 50 malformations 50 thrombophilia 50 untreated tooth decay 50 arterial stiffening 50 vascular inflammation 50 familial hypercholesterolemia 50 nonvertebral fractures 50 bronchopulmonary dysplasia 50 LQTS 50 chronic rhinosinusitis CRS 50 bladder cancers 50 melasma 50 advanced adenoma 50 Irritable Bowel Syndrome IBS 50 carotid plaques 50 ADPKD 50 atopic disorders 50 bisphosphonate drugs 50 hypothyroidism 50 folic acid intake 50 olfactory dysfunction 50 tooth discoloration 50 calcium excretion 50 dietary antioxidants 50 homocysteine 50 genetic predisposition 50 postoperative atrial fibrillation 50 chlamydial infection 50 chronic acid reflux 50 arterial calcification 50 irritable bowel syndrome IBS 50 amyloid deposition 50 non fasting triglycerides 50 neurological abnormalities 50 renal disease 50 dietary sodium 50 adiposity 50 precancerous colon polyps 50 Male pattern baldness 50 choroidal neovascularization 50 postmenopausal 50 Obstructive sleep apnea 50 hereditary disorders 50 Iron deficiency anemia 50 mammary tumors 50 acne lesions 50 periodontal therapy 50 T2DM 50 onychomycosis 50 MGUS 50 gingiva 50 thyroid disorders 50 osteosarcomas 50 microscopic hematuria 50 bacterial colonization 50 sporadic ALS 50 Hurler syndrome 50 FeNO 50 Irritable Bowel Syndrome 50 glaucoma 50 plaque buildup 50 prediabetic 50 potentially modifiable 50 Pseudomonas aeruginosa infections 50 psoriatic 50 Genetic predisposition 50 gallstone formation 50 obese adolescents 50 calcium intake 50 arterial inflammation 50 Hypothyroidism 50 latent TB infection 50 BRCA mutation 50 metabolic syndrome MetS 50 diabetic complications 50 nonalcoholic fatty liver 50 Prostatitis 50 genetic variations 50 obstructive sleep apnea OSA 50 uncontrolled asthma 50 mitochondrial dysfunction 50 glycated hemoglobin levels 50 brittle nails 50 persistent pulmonary hypertension 50 Melasma 50 endotoxins 50 systemic scleroderma 50 vascular calcification 50 prenatal exposures 50 rheumatic disease 50 arterial stiffness 50 periodontal pockets 50 melanocytic nevi 50 leptin resistance 50 homocysteine levels 50 vitamin B# deficiency 50 calcified plaque 50 myocardial infarction 50 dental enamel 50 oral leukoplakia 50 fatal arrhythmias 50 EBV infection 50 magnesium intake 50 prevent tooth decay 50 neovascular AMD 50 genital herpes infections 50 thyroid deficiency 50 APOE e4 50 atopic dermatitis AD 50 lumbar disk herniation 50 peripheral artery disease 50 herpetic 50 telomere length 50 primary hyperparathyroidism 50 cardiac fibrosis 50 tooth enamel 50 blistering sunburns 50 rhinitis 50 vascular reactivity 50 hyperglycaemia 49 Irritable bowel syndrome IBS 49 GERD symptoms 49 aortic valve stenosis 49 secondary hyperparathyroidism 49 fatty liver 49 vertebral fracture 49 B# deficiency 49 advanced adenomas 49 airway hyper responsiveness 49 elevated triglycerides 49 chromosomal abnormalities 49 malabsorption 49 hypertrophic scars 49 folate supplementation 49 iodine intake 49 probiotic supplementation 49 pulmonary hypertension PH 49 Paget disease 49 untreated decay 49 intermittent exotropia 49 elevated IOP 49 familial ALS 49 nonalcoholic steatohepatitis NASH 49 bladder tumors 49 HCV infection 49 airway constriction 49 Marfan syndrome 49 hip fracture 49 recurrent miscarriage 49 node metastases 49 bilateral oophorectomy 49 hemochromatosis 49 serum IgE 49 elevated LDL cholesterol 49 neovascular 49 inflammatory markers 49 precancerous lesions 49 adenoidectomy 49 paraneoplastic 49 geographic atrophy 49 vesicoureteral reflux 49 osteoarthritic 49 autoantibodies 49 DHA supplementation 49 neurocognitive deficits 49 amino acid homocysteine 49 inflammatory acne 49 rectal cancers 49 proteinuria 49 male pattern baldness 49 gastroesophageal reflux GERD 49 sudden sensorineural hearing 49 HPV infections 49 2 diabetes T2D 49 Regular checkups 49 body fatness 49 rosacea 49 endometriosis 49 Fatty Liver Disease 49 T2D 49 uncontrolled epilepsy 49 Dental fluorosis 49 edentulous 49 androgen deficiency 49 Bleeding gums 49 hematuria 49 Helicobacter pylori 49 etiologic 49 hypoglycemic episodes 49 OSAHS 49 calculi 49 biologic plausibility 49 endothelial function 49 abnormal growths 49 metabolic abnormalities 49 autonomic dysfunction 49 respiratory viral infections 49 aspirin therapy 49 precancerous tumors 49 premalignant lesions 49 polycystic ovarian syndrome 49 hyperinsulinemia 49 colon tumors 49 OAB symptoms 49 cariogenic 49 sensorineural hearing loss 49 rhinovirus infection 49 carcinoid tumor 49 Diabetic neuropathy 49 glitazones 49 postoperative delirium 49 genetic variant 49 thyroid hormone levels 49 underactive thyroid gland 49 PBDE exposure 49 prostate cancers 49 APOL1 49 urinary stones 49 myocardial ischemia 49 allergic dermatitis 49 irreversible blindness 49 hepatitis B infection 49 acute otitis media 49 invasive candidiasis 49 Bruxism 49 duodenal ulcers 49 de ath 49 nephropathy 49 gastro oesophageal reflux 49 inflammatory bowel diseases 49 IUGR 49 neurodevelopmental outcome 49 lipid abnormalities 49 spontaneous preterm delivery 49 premalignant 49 neuropsychiatric disorders 49 thicker carotid arteries 49 Sarcopenia 49 Barrett Esophagus 49 dental caries tooth decay 49 inhaled allergens 49 haematuria 49 abnormal vaginal bleeding 49 vitamin D 49 dysfunctional voiding 49 hyperkalemia 49 atherosclerosis hardening 49 dietary fat 49 uveal melanoma 49 cardiac dysfunction 49 thromboembolic 49 corneal ectasia 49 androgenic alopecia 49 CMV disease 49 allergic asthma 49 allergic sensitization 49 statin therapy 49 #,# DCB 49 lung function 49 onset diabetes mellitus 49 chlamydial 49 Helicobacter pylori H. pylori 49 alveolar bone 49 ischemic vascular 49 myeloperoxidase 49 diabetic kidney 49 S. aureus colonization 49 chorioamnionitis 49 p# mutations 49 premenstrual syndrome PMS 49 postoperative ileus 49 calcium intakes 49 clefting 49 cancerous polyps 49 ONJ 49 acute GVHD 49 prehypertension 49 atypical fractures 49 herpes simplex encephalitis 49 Peripheral arterial disease 49 dilated eye 49 Seborrheic dermatitis 49 posterior vitreous detachment 49 gene variant 49 CC genotype 48 reflux esophagitis 48 RBP4 48 temporal arteritis 48 hypercalciuria 48 macular edema 48 asthma 48 C. pneumoniae 48 Fungal infection 48 Fluorosis 48 organophosphate exposure 48 Cavities 48 dyslipidemia 48 photodamage 48 extrapyramidal symptoms 48 heartworm disease 48 decayed teeth 48 pelvic inflammatory disease 48 ear infections 48 pathologic fractures 48 vitamin E 48 kidney function 48 calcification 48 asymptomatic 48 cardiometabolic risk 48 asymptomatic carotid stenosis 48 Metabolic Syndrome 48 ischemic mitral regurgitation 48 heterozygous FH 48 mammary gland tumors 48 esophageal adenocarcinoma 48 kidney insufficiency 48 Prehypertension 48 iron deficiency anemia 48 BRCA mutations 48 carbohydrate intolerance 48 gastric ulcers 48 bullous 48 cartilage degeneration 48 dietary folate 48 STAT4 48 atherosclerotic 48 bicuspid aortic valves 48 vaginal yeast infections 48 colorectal cancers 48 vessel occlusion 48 gene variants 48 neuropathies 48 SRBD 48 hereditary hemochromatosis 48 diabetic microvascular complications 48 Framingham Offspring Study 48 Morbid obesity 48 restenosis 48 Leber congenital amaurosis LCA 48 B7 H3 48 plasma kallikrein 48 hypophosphatasia 48 nasal allergies 48 staphylococcal infections 48 yeast overgrowth 48 microbleeds 48 cancers 48 empyema 48 gout 48 cotinine 48 cognitive dysfunction 48 endotoxin exposure 48 colorectal neoplasms 48 Chronic constipation 48 peripheral arterial disease 48 alcoholic fatty liver 48 adenomatous 48 keloid formation 48 chronic kidney 48 HeFH 48 nevi 48 trans palmitoleic acid 48 RSV infection 48 giant cell arteritis 48 Parkinson disease PD 48 aortic atherosclerosis 48 precancerous polyp 48 FMRP protein 48 dietary intakes 48 selenium intake 48 xylitol 48 facial redness 48 dysglycemia 48 Cholangiocarcinoma 48 choriocarcinoma 48 basal cell cancers 48 BRCA gene mutations 48 mtDNA mutations 48 testosterone deficiency 48 APOE e4 gene 48 glycation 48 Helicobacter pylori bacteria 48 gastric adenocarcinoma 48 subclinical disease 48 Androgenetic Alopecia 48 neural tube birth defects 48 hallux valgus 48 hyperlipidaemia 48 shorter telomeres 48 dental caries cavities 48 bone density 48 skin cancers 48 filaggrin mutations 48 keloids 48 coronary artery calcification 48 gestational hypertension 48 Varicose veins 48 earwax 48 parathyroid carcinoma 48 pseudotumor cerebri 48 invasive meningococcal disease 48 adequate calcium intake 48 obesity insulin resistance 48 thyrotropin levels 48 fasting glucose levels 48 hypercalcemia 48 oesophageal cancer 48 coagulation abnormalities 48 nonfasting triglycerides 48 anal cancers 48 left ventricular dysfunction 48 cognitive impairment 48 primary ovarian insufficiency 48 hyperglycemia 48 gynecomastia 48 contrast induced nephropathy 48 MYH9 48 allergic rhinitis 48 cirrhosis 48 recurrent VTE 48 SHPT 48 Pulmonary hypertension 48 cerebral infarction 48 testicular tumors 48 nonadherence 48 Genital herpes 48 ichthyosis vulgaris 48 vascular diseases 48 Porphyromonas gingivalis 48 Heavy snorers 48 amyloid deposits 48 hypocalcaemia 48 habitual snoring 48 chromosomal instability 48 triglyceride levels 48 prostate cancer CaP 48 overt nephropathy 48 serum uric acid 48 exhaled nitric oxide 48 infective endocarditis 48 atopic asthma 48 precancerous cervical 48 undergoing radical prostatectomy 48 hyperhomocysteinemia 48 upper gastrointestinal bleeding 48 elevated serum ALT 48 ulcerations 48 secondary amenorrhea 48 postoperative AF 48 esophageal squamous cell carcinoma 48 interstitial cystitis 48 Haptoglobin 48 insulin sensitivity 48 NF1 48 AAT Deficiency 48 untreated sleep apnea 48 leiomyomas 48 bacterial prostatitis 48 DDS Ph.D. 48 Candida overgrowth 48 allergic diseases 48 squamous cell cancers 48 oral bisphosphonates 48 urinary oxalate 48 hypertensives 48 coronary artery atherosclerosis 48 juvenile idiopathic arthritis 48 neurodevelopment 48 invasive fungal infection 48 severe psoriasis 48 thrombotic events 48 recurrent kidney stones 48 abnormal uterine bleeding 48 chronic HCV infection 48 endometrial lining 48 inflammatory rheumatic 48 hardened arteries 48 oesophageal adenocarcinoma 48 atrophic gastritis 48 sarcopenia 48 pouchitis 48 Bacterial vaginosis 48 nutritional deficiency 48 transferrin saturation 48 Chronic insomnia 48 bone thinning 48 mild fluorosis 48 adrenal tumors 48 bone fracture 48 chronic sinus infections 48 peptic ulcers 48 urinary infections 48 hyperuricemia 48 insulin secretion 48 hypopigmentation 48 Wernicke encephalopathy 48 digestive tract cancers 48 dietary calcium intake 48 masticatory 48 congenital CMV 48 CHD 48 ASDs 48 acne rosacea 48 ocular toxicity 48 bexarotene 48 prematurity ROP 48 knee osteoarthritis OA 48 silent myocardial ischemia 48 acne 48 gingival tissue 48 oxidized LDL 48 telogen effluvium 48 Non Alcoholic Fatty 48 primary biliary cirrhosis 48 dominantly inherited 48 indoor allergens 48 vestibular dysfunction 48 G6PD deficiency 48 gastroesophageal reflux 48 lung lesions 48 brain lesions 48 cystic acne 48 genetic polymorphisms 48 heterotaxy 48 nasal polyps 48 insulin resistance precursor 48 BRCA2 mutations 48 Heavy menstrual bleeding 48 fatty acid oxidation 48 CA MRSA infections 48 aortic aneurysms 48 gestational diabetes mellitus GDM 48 lipid levels 48 GH deficiency 48 osteopontin 48 atherothrombotic disease 48 testicular germ cell 48 herpes zoster infection 48 ocular disorders 48 platelet activation 48 benign polyps 48 leukoplakia 48 postoperative morbidity 48 carotenoid antioxidants 48 osteonecrosis 48 basal cell carcinoma BCC 48 periodontal tissues 48 herpes zoster 48 depressive symptoms 48 fluoride toothpaste 48 celiac disease 48 urethritis 48 diabetic peripheral neuropathy 48 congenital disorders 48 thromboembolic disease 48 dietary fiber 48 Eye Disease 47 unexplained infertility 47 Gorlin syndrome 47 Ascherio 47 symptomatic benign prostatic 47 magnesium supplementation 47 hyperemesis gravidarum 47 halitosis 47 gingival inflammation 47 macroalbuminuria 47 Periodontal diseases 47 toxoplasmosis 47 belly fat 47 menstrual irregularity 47 glucocorticoid therapy 47 oral rinse 47 kidney disease 47 malignant polyps 47 liver cirrhosis 47 specific IgE 47 NP CRNs 47 Zinc deficiency 47 congenital malformations 47 obstructive coronary artery 47 thromboembolism 47 celiac sprue 47 corneal ulceration 47 autoimmune thyroid 47 thrombotic complications 47 thoracic aortic disease 47 sudden cardiac death 47 myocardial fibrosis 47 pleural mesothelioma 47 penile cancers 47 liver scarring 47 radioiodine therapy 47 vasculopathy 47 refractory gout 47 dietary intake 47 Candidiasis 47 untreated cavities 47 Polycystic ovary syndrome PCOS 47 TMJD 47 acetabular dysplasia 47 salivary function 47 retinoids 47 rheumatic diseases 47 abnormal lipid levels 47 thiopurine 47 immunosuppressive therapies 47 gastro esophageal reflux disease 47 NF2 47 breast endometrial 47 asthma eczema 47 Thiamine 47 lumbar disc disease 47 von Willebrand disease 47 bronchial hyperresponsiveness 47 PsA 47 gonococcal infection 47 Homocysteine 47 postnatal depression 47 intractable epilepsy 47 fructose intake 47 Secondhand smoke exposure 47 bladder cancer 47 metabolic acidosis 47 hepatic toxicity 47 lumbar spinal stenosis 47 uric acid 47 inflamed gums 47 Chronic sinusitis 47 biphosphonates 47 preeclamptic 47 preterm infants 47 Bisphosphonate 47 contact dermatitis 47 congenital abnormalities 47 vitamin supplementation 47 hepatic fibrosis 47 ovarian function 47 blepharitis 47 primary hyperoxaluria 47 reflux 47 oral antidiabetic medication 47 disordered breathing 47 upper airway obstruction 47 intermittent hypoxia 47 degenerative retinal diseases 47 hip fractures 47 anterior uveitis 47 dose ionizing radiation 47 Dental implants 47 asymptomatic PAD 47 psoriasis vulgaris 47 zinc deficiency 47 calcium absorption