Low calcium:phosphorus ratio in habitual diets affects serum parathyroid hormone concentration and calcium metabolism in healthy women with adequate calcium intake.

Excessive dietary P intake alone can be deleterious to bone through increased parathyroid hormone (PTH) secretion, but adverse effects on bone increase when dietary Ca intake is low. In many countries, P intake is abundant, whereas Ca intake fails to meet recommendations; an optimal dietary Ca:P ratio is therefore difficult to achieve. Our objective was to investigate how habitual dietary Ca:P ratio affects serum PTH (S-PTH) concentration and other Ca metabolism markers in a population with generally adequate Ca intake. In this cross-sectional analysis of 147 healthy women aged 31-43 years, fasting blood samples and three separate 24-h urinary samples were collected. Participants kept a 4-d food record and were divided into quartiles according to their dietary Ca:P ratios. The 1st quartile with Ca:P molar ratio < or = 0.50 differed significantly from the 2nd (Ca:P molar ratio 0.51-0.57), 3rd (Ca:P molar ratio 0.58-0.64) and 4th (Ca:P molar ratio > or = 0.65) quartiles by interfering with Ca metabolism. In the 1st quartile, mean S-PTH concentration (P = 0.021) and mean urinary Ca (U-Ca) excretion were higher (P = 0.051) than in all other quartiles. These findings suggest that in habitual diets low Ca:P ratios may interfere with homoeostasis of Ca metabolism and increase bone resorption, as indicated by higher S-PTH and U-Ca levels. Because low habitual dietary Ca:P ratios are common in Western diets, more attention should be focused on decreasing excessively high dietary P intake and increasing Ca intake to the recommended level.

Genetic lactase non-persistence, consumption of milk products and intakes of milk nutrients in Finns from childhood to young adulthood.

Previous evidence suggests that the lactase gene C/T- 13910 polymorphism (rs4988235) is associated with avoidance of milk products and lower Ca intake. We examined whether the consumption of milk and milk products and the intakes of milk nutrients differ between the lactase genotypes from childhood to young adulthood. Subjects belong to the Cardiovascular Risk in Young Finns Study where the first cross-sectional surveys were conducted in 1980 (n 3596), with follow-up studies in 1983, 1986, 1989, 1992 and 2001 (n 2620). The same dietary questionnaire was used throughout the follow-up to collect data on habitual consumption of milk and milk products in all subjects, and daily nutrient intakes were assessed with 48 h dietary recalls in 50 % of the subjects. Subjects with the lactase non-persistence (C/C- 13910) genotype consumed less milk since childhood, but the consumption of other milk products did not differ between the genotypes. In adult females, the lactose content of milk products consumed was lower (P = 0.003), and in both sexes low-lactose and milk-free diets were more common in the C/C- 13910 genotype than in the other genotypes. Inadequate Ca intake was most common in females with the C/C- 13910 genotype as early as in childhood (15-63 %), but in males only in adulthood (24 %). In adult females, preference for low-lactose milk and milk products equalised the differences in Ca intake between the genotypes. Thus, in those with the C/C- 13910 genotype, preference for low-lactose milk and milk products may decrease the risk for inadequate Ca intake.

Long-term dietary patterns and carotid artery intima media thickness: the Cardiovascular Risk in Young Finns Study.

A whole-diet approach has proven useful for characterising dietary exposure in cardiovascular epidemiology research. In our previous analyses, we found dietary patterns to be significant determinants of CVD risk factor levels among the Cardiovascular Risk in Young Finns cohort. We investigated the associations of major dietary patterns with carotid intima media thickness (IMT), a subclinical predictor of CVD, in healthy adults. The Young Finns Study is an ongoing, prospective cohort study with a 21-year follow-up to date. The subjects were children and adolescents at baseline in 1980 (aged 3-18 years), and all had reached adulthood by the latest follow-up in 2001 (aged 24-39 years). Complete dietary data from the years 1980, 1986 and 2001 and outcome data from the year 2001 were obtained from 785 subjects. The long-term average pattern score for a traditional dietary pattern (characterised by high consumption of rye, potatoes, butter, sausages, milk and coffee) was associated with IMT especially among subjects with a low score for the health-conscious dietary pattern (characterised by high consumption of vegetables, legumes and nuts, rye, tea, cheese and other dairy products). In multivariable regression analyses using long-term pattern scores as predictors, the traditional dietary pattern was independently associated with IMT in men (P < 0.01), but not in women (P = 0.66). Long-term adherence to traditional food choices seems to increase the risk of developing subclinical atherosclerosis among Finnish men.

Associations of genetic lactase non-persistence and sex with bone loss in young adulthood.

Some studies have reported that after attainment of peak bone mass (PBM), slow bone loss may occur in both men and women; however, findings are inconsistent. Genetic factors play a significant role in bone loss, but the available evidence is conflicting. Genetic lactase non-persistence (lactase C/C(-13910) genotype) is suggested to increase risk for inadequate calcium intake predisposing to poorer bone health. We investigated whether this genotype is associated with PBM and bone loss in young Finnish adults. Subjects belong to the Cardiovascular Risk in Young Finns Study that is an ongoing multi-centre follow-up of atherosclerosis risk factors. From the original cohort, randomly selected subjects aged 20-29 participated in baseline bone mineral density (BMD) measurements (n=358), and in follow-up measurements 12 years later (n=157). Bone mineral content (BMC) and BMD at lumbar spine (LS) and femoral neck (FN) were measured at baseline and follow-up with dual energy X-ray absorptiometry (DXA). Lactase C/T(-13910) polymorphism was determined by PCR and allele-specific fluorogenic probes. Information on lifestyle was elicited with questionnaires. During the follow-up, bone loss at both bone sites was greater in males (LS BMD: -1.1%, FN BMD: -5.2%) than in females (LS BMD: +2.1%, FN BMD: -0.7%) (both bone sites p=0.001). Younger age predicted greater loss of FN BMC and BMD in females (p=0.013 and p=0.001, respectively). Increased calcium intake predicted FN BMD gain in both sexes (in females B=0.007 g/cm(2)/mg, p=0.002; in males B=0.006, p=0.045), and increased physical activity LS BMD gain in females (B=0.091 g/cm(2)/physical activity point, p=0.023). PBM did not differ between the lactase genotypes, but males with the CC(-13910) genotype seemed to be prone to greater bone loss during the follow-up (LS BMD: C/C vs. T/T p=0.081). In conclusion, bone loss in young adulthood was more common in males than in females and seemed to occur mainly at the femoral neck. Young males with the lactase CC(-13910) genotype may be more susceptible to bone loss; however, calcium intake predicts changes in bone mass more than the lactase genotype.

Vitamin D receptor gene start codon polymorphism (FokI) is associated with forearm bone mineral density and calcaneal ultrasound in Finnish adolescent boys but not in girls.

We examined the association between vitamin D receptor (VDR) gene FokI polymorphism and bone mineral density and quantitative ultrasound parameters in Finnish adolescents. We assessed bone mineral density at the distal sites of radius and ulna, quantitative ultrasound of the calcaneus, serum concentration of 25-hydroxyvitamin D (25-OHD), calcium intake, physical activity, and BsmI and FokI polymorphisms of the vitamin D receptor gene in 86 girls and 38 boys aged 14 to 16 years. In girls, FokI polymorphism was not significantly associated with bone mineral density or quantitative ultrasound parameters. In adolescent boys, the Ff genotype was associated with higher forearm BMD and calcaneal ultrasound values, when adjusted for body and bone size, BsmI polymorphism, calcium intake, vitamin D status, smoking, and physical activity.