Association of body fat and vitamin D status and the effect of body fat on the response to vitamin D supplementation in Pakistani immigrants in Denmark.

Vitamin D deficiency and obesity are both prevalent conditions in the northern countries, especially among immigrants. The aims were to assess the possible relationship between body fat and vitamin D status, and to investigate the effect of body fat on the response to oral vitamin D supplementation in Pakistani immigrants in Denmark. Data were obtained from a 1-year double-blind randomised controlled trial with oral vitamin D supplementation. A total of 122 women and men received either vitamin D3 supplementation (10 or 20 µg/day) or placebo. No association was found between body fat percentage and vitamin D status in a multiple linear regression model (P<0.001). No effect of body fat was seen on the vitamin D status response following the intervention with vitamin D. In conclusion, there was no baseline association between body fat percentage and vitamin D status, and body fat percentage had no effect on the response to vitamin D supplementation.

Seasonal changes in vitamin D status among Danish adolescent girls and elderly women: the influence of sun exposure and vitamin D intake.

BACKGROUND/OBJECTIVES: To determine seasonal variation in vitamin D status in healthy Caucasian adolescent girls and elderly community-dwelling women living in Denmark, and to quantify the impact of sun exposure and intake on the seasonal changes in vitamin D status. SUBJECTS/METHODS: A 1-year longitudinal observational study of 54 girls (11-13 years) and 52 women (70-75 years). The participants were examined three times (winter-summer-winter). Serum 25-hydroxyvitamin D (S-25OHD) concentration and vitamin D intake were measured at each visit. Sun exposure was measured during summer. RESULTS: S-25OHD concentrations (winter, summer, winter) were median (25, 75 percentiles) 23.4 (16.5, 36.4), 60.3 (42.7, 67.7), 29.5 (22.2, 40.4) and 47.2 (27.3, 61.1), 67.3 (35.1, 79.2), 50.5 (32.7, 65.5)nmol/l for girls and women, respectively. The usual sun habits were determinant (P=0.002) for change in vitamin D status from winter to summer. Vitamin D intake from supplements (P<0.0001) and diet (P=0.002) were determinants for change in vitamin D status from summer to winter. Winter vitamin D status of 50 nmol/l is achievable when vitamin D status the previous summer was ≈ 100 nmol/l. If summer vitamin D status is only ≈ 60 nmol/l, vitamin D status the following winter would be ≈ 28 nmol/l. CONCLUSIONS: Low vitamin D status among adolescent girls and elderly women during two consecutive winter seasons, improved vitamin D status during the summer and better vitamin D status in women than in girls was found. The estimations show that a summer S-25OHD concentration ≈ 100 nmol/l is needed to achieve a concentration of ≈ 50 nmol/l the following winter.

Determinants of vitamin D status in a general population of Danish adults.

BACKGROUND AND AIMS: Danish legislation regarding food fortification has been very restrictive and vitamin D deficiency is thought to be common in Denmark due to inadequate dietary intakes and the fact that in Denmark (latitude 56°N) vitamin D is only synthesized in the skin after exposure to solar radiation during summertime (April-September). The purpose of this study was to evaluate the vitamin D status of a general adult population in Denmark and, in addition, associations between vitamin D status and distinct lifestyle factors were studied. METHODS: A random sample of 6784 persons from a general population aged 30-60 years participated in a health examination in 1999-2001. Serum samples from all participants were stored and levels of 25-hydroxyvitamin D (25(OH)D) were measured by HPLC in 2009. The method was compared to another HPLC method. Information on dietary intake of vitamin D and other lifestyle factors were obtained by questionnaires. A total of 6146 persons defined as ethnic Danes and with successful measurements of 25(OH)D were included in the analyses. RESULTS: The overall prevalence of vitamin D deficiency (25(OH)D<25 nmol/l) and insufficiency (25(OH)D<50 nmol/l) were 13.8% and 52.2%, respectively. A marked seasonal fluctuation was seen in serum levels of 25(OH)D - median values of 25(OH)D were lowest in February and highest in August. In multiple logistic regression models (n=5506), low vitamin D status was significantly associated with obesity (BMI≥30), daily smoking and a sedentary lifestyle. However, measurements of 25(OH)D were not associated with the estimated dietary intake of vitamin D. Comparison of two HPLC methods demonstrated considerable differences in accuracy. DISCUSSION AND CONCLUSIONS: Our results suggest that poor vitamin D status is common among adults in a Northern European country without food fortification with vitamin D. Methodological issues are, however, of great importance when using cut-off values to define poor vitamin D status. In addition, we demonstrated that low serum levels of 25(OH)D were associated with several lifestyle factors.

Atopy, asthma, and lung function in relation to folate and vitamin B(12) in adults.

BACKGROUND: Recent studies suggested low serum folate and impaired folate metabolism as potential risk factors for development of asthma and atopic disease, but the results are inconsistent. The aim of this study was to investigate the relations of markers of folate and vitamin B12 (B12) deficiency with different phenotypes of asthma and atopy. METHODS: A random sample of 6784 persons from a general population aged 30-60 years participated in a health examination in 1999-2001, and 4516 (66.6%) of those also participated in a follow-up examination 5 years later. The examinations included spirometry, measurements of serum folate and B12, specific IgE to inhalant allergens, total IgE, and genotyping of the MTHFR-C677T polymorphism - a genetic marker of impaired folate metabolism. Information about dietary intake of folate and B12, asthma diagnosis, and airway symptoms was obtained by questionnaires. RESULTS: Low serum folate levels and the TT genotype of the MTHFR-C677T polymorphism were associated with increased prevalence of self-reported doctor-diagnosed asthma [odds ratio (OR) 1.37, 95% confidence interval (CI) 1.05-1.79 and OR 1.52; 95% CI 1.12-2.06, respectively] and attacks of shortness of breath (OR 1.43, 95% CI 1.14-1.79 and OR 1.47; 95% CI: 1.14-1.91, respectively). We found no significant associations with lung function or atopic outcomes. Serum levels of B12 and dietary intake of folate and B12 were not associated with asthma or atopy. CONCLUSIONS: We found that two objective markers of folate deficiency were associated with self-reported doctor-diagnosed asthma and attacks of shortness of breath, but not with lung function or atopy.

Vitamin D supplementation does not affect serum lipids and lipoproteins in Pakistani immigrants.

Potential long-term negative effects of increased vitamin D consumption are not thoroughly examined. The aim of this study was to investigate possible negative effects of vitamin D supplementation on serum lipids and lipoproteins. A 1-year long randomised double-blinded placebo-controlled intervention study with two doses of vitamin D3 (10 and 20 microg/day) was carried out among 89 women (18-53 years of age) and 84 men (18-64 years of age) of Pakistani origin living in Denmark with low vitamin D status. This study did not find changes in total cholesterol, LDL-cholesterol, HDL-cholesterol, LDL-cholesterol/HDL-cholesterol ratio, VLDL-cholesterol and triacylglycerol after daily supplementation with 10 or 20 microg vitamin D for 1 year. In conclusion, increasing the vitamin D intake by 10-20 microg per day for 1 year is safe for Pakistani immigrants with regards to serum lipids and lipoproteins.

Relative validity of a food frequency questionnaire used in the Inter99 study.

OBJECTIVE: To evaluate the validity of the Inter99 food frequency questionnaire (FFQ) compared with a 28-days' diet history and biomarkers. SUBJECTS: A random sample of 13 016 individuals were drawn from a general population and invited for a health screening programme. Participation rate was 52.5%. All high-risk individuals were re-invited for assessment after 1 and 3 years and completed a 198-item FFQ at all three occasions. Participants attending for 3 years follow-up were invited to participate in the validation study, including a 28-days' diet history, a 24-h urine collection and a fasting blood sample. Overall, 264 subjects participated. RESULTS: Spearman's rank correlation coefficients between the two dietary methods ranged from 0.31(beta-carotene) to 0.64 (fruits) in men and from 0.31 (polyunsaturated fat and sodium) to 0.64 (fruits) for women. The proportion of individuals classified in the same or adjacent quintiles were, on average, 72% for men and 69% for women. Gross misclassification was found on average in 2%. The correlation coefficients of the residuals ranged from 0.27 (sodium) to 0.61 (fruits) for men and from 0.21 (sodium) to 0.62 (B12-vitamin) for women. Correlation coefficients between fruit and vegetable intake and carotenoids ranged from -0.08 (lycopene) to 0.44 (alpha-carotene). For the residuals the correlation coefficients ranged from -0.004 (lycopene) to 0.47 (alpha-carotene). CONCLUSION: The Inter99 FFQ and the residuals of the intake provide acceptable classification of individuals according to their dietary intakes and the FFQ gives a good quantitative measurement of key dietary components.

Pakistani immigrant children and adults in Denmark have severely low vitamin D status.

OBJECTIVE: To determine vitamin D and bone status in adolescent girls, pre-menopausal women and men of Pakistani origin, to single out determinants of vitamin D status and to determine the association between vitamin D status, bone metabolism and bone status. SUBJECTS/METHODS: Cross-sectional study, Copenhagen (55 degrees N), January-November. Serum 25-hydroxyvitamin D (S-25OHD), serum intact parathyroid hormone (S-iPTH), bone turnover markers and whole body and lumbar spine bone mineral density were measured. Sun, smoking and clothing habits, age, body mass index (BMI), and vitamin D and calcium from food and from supplements were recorded. Thirty-seven girls (median age, range: 12.2 years, 10.1-14.7), 115 women (36.2 years, 18.1-52.7) and 95 men (38.3 years, 17.9-63.5) of Pakistani origin (immigrants or descendants with Pakistani parents) took part in the study. RESULTS: Median concentration of S-25OHD was 10.9, 12.0 and 20.7 nmol/l for girls, women and men, respectively. Forty-seven per cent of the girls, 37% of the women and 24% of the men had elevated S-iPTH, and there was a negative relationship between S-iPTH and S-25OHD. Use of vitamin D-containing supplements had a positive association with S-25OHD for men (P=0.04) and women (P=0.0008). Twenty-one per cent of the women and 34% of the men had osteopenia. Neither S-25OHD nor S-iPTH was associated with lumbar spine or whole body bone mineral content. CONCLUSIONS: Severely low vitamin D status and elevated S-iPTH is common among Pakistani immigrants in Denmark. The low vitamin D status is not associated with bone markers or bone mass among relatively young Pakistanis.

Evaluating iodine deficiency in pregnant women and young infants-complex physiology with a risk of misinterpretation.

OBJECTIVE: To review methods for evaluating iodine deficiency in pregnant women and young infants and to discuss factors to be considered in the interpretation of their results. DESIGN: Review of the literature regarding the various methods available for assessing iodine status. SETTING: Population surveys and research studies. SUBJECTS: Pregnant women and young infants. RESULTS: Several factors to consider when assessing iodine status in pregnant women and young infants include: 1) the urinary iodine (UI) concentration (microg l-1) is not interchangeable with 24 h UI excretion (microg per 24 h); 2) the concentration of iodine in a spot or casual urine sample cannot be used to diagnose iodine deficiency in an individual; 3) a moderate fall in the concentration of serum free T4 during pregnancy is not a sign of maternal iodine deficiency; 4) an increase in the concentration of serum thyroglobulin (Tg) during pregnancy is not a sign of maternal iodine deficiency; 5) a higher concentration of TSH and Tg in cord blood than in maternal blood is not a sign of iodine deficiency in the mother or neonate; and 6) thyroid function in a full-term foetus, a neonate or a small child is not more sensitive to a mild iodine deficiency than in the mother. CONCLUSIONS: If the iodine status of pregnant women and small children is not to be misjudged, the above six factors need to be taken into account.

Teenage girls and elderly women living in northern Europe have low winter vitamin D status.

OBJECTIVE: To determine the vitamin D status (serum 25-hydroxyvitamin D; S-25OHD) in adolescent girls and elderly community-dwelling women living in four countries of northern Europe and to explain differences in S-25OHD concentrations between and within the countries. DESIGN: A cross-sectional observational study conducted in a standardised way during February-March. S-25OHD was analysed by high-performance liquid chromatography. Vitamin D and calcium intake was calculated using a standardised food composition database. SETTING: Denmark, Finland, Ireland, and Poland. SUBJECTS: A total of 199 girls (mean (s.d.) age 12.6 (0.5) y) and 221 women (mean (s.d.) age 71.8 (1.4) y). RESULTS: The median (inter quartiles) concentration of S-25OHD was 29.4 (20.3, 38.3) nmol/l for the girls and 40.7 (28.0, 54.2) nmol/l for the women. S-25OHD below 25 nmol/l was found in 37% of the girls and 17% of the women, and S-25OHD below 50 nmol/l was found in 92% of the girls and 37% of the women. Positive significant determinants for S-25OHD in girls were use of vitamin D supplements, and in women sun habits, dietary vitamin D intake, use of vitamin D and calcium supplements. Body mass index and smoking were negative determinants in women. For women predictors could explain the differences between countries (P(country) = 0.09, R(2) = 0.39), but for girls the difference remained significant even after including predictors (P(country) = 0.03, R(2) = 0.15). CONCLUSION: Vitamin D status is low in northern Europe during winter. More than one-third of the adolescent girls have vitamin D status below 25 nmol/l and almost all are below 50 nmol/l. Two-thirds of the elderly community-dwelling women have vitamin D status below 50 nmol/l. Use of vitamin D supplements is a significant positive determinant for S-25OHD for both girls and women (P = 0.001). SPONSORSHIP: The European Fifth Framework Programme (Contract No. QLK1-CT-2000-00623).

Skipping of meals has a significant impact on dietary intake and nutritional status of old (65+ y) nursing home residents.

BACKGROUND: In spite of a high prevalence of undernutrition among old nursing home residents, studies have generally reported a mean intake of energy sufficient to cover the mean estimated energy requirement. This discrepancy could be due to skipping of meals and hence periods of insufficient energy intake too intermittent to be identified, when mean results are presented. OBJECTIVE: To examine the significance of skipping of (part of) meals on dietary intake and nutritional status of old (65+y) nursing home residents. DESIGN: Participants were 132 nursing home residents (84 (82-85) y). They were characterised according to activity of daily living-functions (ADL-functions), cognitive performance, intake of energy and protein (4-days dietary record), skipping of meals, energy and protein balance, and nutritional status (body mass index (BMI)). RESULTS: The participants had an energy intake, which was significantly higher than the estimated energy requirement (p <0.001). However, 41 (31%) had nothing to eat or only had desert at one or more meals during the 4-day registration period. Participants who were skipping meals had a lower BMI, energy and protein intake (all p <0.001) and a higher prevalence of negative protein balance (p <0.01), than the other residents. CONCLUSION: More focus should be given to individualized nutritional assessment in order to discover the cause to this problem and target individuals who could be helped by nutritional intervention.

Effect of a high-protein, high-salt diet on calcium and bone metabolism in postmenopausal women stratified by hormone replacement therapy use.

The objective of this study was to investigate the influence of a high-sodium, high-protein diet on bone metabolism in postmenopausal women (aged 49-60 y) stratified by hormone replacement therapy (HRT) use. In a crossover trial, 18 women (n = 8 HRT users (+HRT) and n = 10 nonusers (-HRT)) were randomly assigned to a diet high in protein (90 g/day) and sodium (180 mmol/day) (calciuric diet) or a diet moderate in protein (70 g/day) and low in sodium (65 mmol/day) for 4 weeks followed by crossover to alternative dietary regimen for a further 4 weeks. The calciuric diet significantly (P < 0.05) increased urinary sodium, calcium and nitrogen in both groups. While the calciuric diet increased urinary N-telopeptide crosslinks of collagen (by approximately 25%, P = 0.003) in the -HRT group, it had no effect in the +HRT group. It appears that postmenopausal HRT use attenuates the increase in a marker of bone resorption associated with a calciuric diet.

Low socio-economic status and familial occurrence of goitre are associated with a high prevalence of goitre.

The occurrence of goitre is dependent on genetic and environmental factors, but the associations with socio-economic and life-style factors have only been examined briefly. A cohort of 4649 participants from the general population was examined with questionnaires, thyroid ultrasonography, clinical examination and blood tests. Data were analysed in linear models and logistic regression analysis. Thyroid volume and serum thyroglobulin were closely associated with educational level with higher values in the group with the lowest levels of education (p < 0.001). The same pattern applied to thyroid multinodularity at ultrasonography (p = 0.002) and palpable goitre (p = 0.01). Physical activity in leisure time was negatively associated with thyroid enlargement (p = 0.02) and serum thyroglobulin (p < 0.001). These associations diminished markedly if adjustment was made for smoking habits, alcohol consumption and iodine intake. Familial occurrence of goitre was associated with goitre prevalence (Odds Ratio 2.5, 95% CI: 1.6-3.9), but did not confound the socio-economic associations. In conclusion, social imbalances in the occurrence of goitre were identified. These imbalances could in part be explained by differences in smoking habits and iodine intake.

Para-aminobenzoic acid (PABA) used as a marker for completeness of 24 hour urine: effects of age and dosage scheduling.

OBJECTIVE: To examine the age dependency of the urinary para-aminobenzoic acid (PABA) excretion, and if a delayed PABA excretion can be overcome by advancing intake schedule; and to examine the recovery of PABA in fractionated urinary samples collected during 24 h after single and repeated doses of PABA. DESIGN: Cross-over study with subjects randomized to start with recommended schedule of PABA administration (80 mg at 08:00, 12:00 and 18:00; PABA18) and then an advanced schedule (80 mg at 08:00, 12:00 and 15:00; PABA15) or vice versa. One subgroup of eight subjects collected individual urine specimens for 24 h after a morning dose of 80 mg of PABA, and another subgroup of 10 subjects collected individual urine specimens for 24 h after ingestion of 80 mg of PABA three times at mealtimes. SUBJECTS: Employees and relatives from the Danish Food Administration. SETTING: Ninety-nine healthy volunteers (61 females and 38 males) aged 30-91 y. RESULTS: Linear regressions for PABA15 and PABA18 demonstrate significantly less recovery with age (PABA15: r(2)=0.1784, P=0.0002; PABA18: r(2)=0.1273, P=0.0019). Linear regression of DeltaPABA (PABA15-PABA18) with age showed the best fit line to be horizontal (slope -0.0066, P=0.89; 95% CI -0.1046, 0.0915) and with a Y-intercept not significantly different from 0 (1.575; 95% CI -4.176, 7.326). In this population the lower limit for complete 24 h urine collection was 79.2%. After a single dosage of 80 mg PABA 70-85% was recovered after 8 h. Within 16 h after ingestion of 240 mg PABA at recommended hours the lowest acceptable recovery (78.1%) was reached. CONCLUSION: There is a gradual decline of PABA recovery with age that cannot be overcome by advancing the dosage schedule. Because of a lower delimiting PABA recovery for the elderly, some 24 h collections in this age group will be rejected unjustly (false-negatives). Also, with the currently recommended dosage schedule (PABA taken with the main meals) the risk of false-positive 24 h urine collections prevails. With refinement of the PABA test procedure, ie employing a specific analytical method and age-dependent cut-off values, the test may achieve a higher specificity and sensitivity.