Self-rated health in individuals with and without disease is associated with multiple biomarkers representing multiple biological domains.

Self-rated health (SRH) is one of the most frequently used indicators in health and social research. Its robust association with mortality in very different populations implies that it is a comprehensive measure of health status and may even reflect the condition of the human organism beyond clinical diagnoses. Yet the biological basis of SRH is poorly understood. We used data from three independent European population samples (N approx. 15,000) to investigate the associations of SRH with 150 biomolecules in blood or urine (biomarkers). Altogether 57 biomarkers representing different organ systems were associated with SRH. In almost half of the cases the association was independent of disease and physical functioning. Biomarkers weakened but did not remove the association between SRH and mortality. We propose three potential pathways through which biomarkers may be incorporated into an individual's subjective health assessment, including (1) their role in clinical diseases; (2) their association with health-related lifestyles; and (3) their potential to stimulate physical sensations through interoceptive mechanisms. Our findings indicate that SRH has a solid biological basis and it is a valid but non-specific indicator of the biological condition of the human organism.

Relation of DDT residues to plasma retinol, alpha-tocopherol, and beta-carotene during pregnancy and malaria infection: a case-control study in Karen women in northern Thailand.

Populations living in endemic malaria areas maybe exposed simultaneously to DDT and malaria infection. DDT may impair status of vitamins, which are implicated in the immunity and pathophysiology of malaria. To explore possible interactions, DDT residues, retinol, alpha-tocopherol, beta-carotene and cholesterol were measured in plasma samples of malaria-infected pregnant women (cases, n=50) and age matched malaria-free controls (n=58). DDT residues were found in all samples: mean (sd) total DDT levels of 29.7 and 32.7 ng/ml in cases and controls, respectively. Mean (sd) p,p'-DDT was higher in the controls than the cases (13.5 vs. 9.5 ng/ml, p=0.006). Malaria infection was associated with lower mean (sd) plasma retinol (0.69 vs. 1.23 micromol/L) and cholesterol (2.62 vs. 3.48 mmol/L) compared to controls (p<0.001). Mean (sd) plasma alpha-tocopherol (7.65 vs. 15.58 micromol/L) and alpha-tocopherol/cholesterol ratio (2.3 vs. 6.7 micromol/L/mmol/L) were significantly lower among the controls (p<0.001). Mean (sd) plasma beta-carotene was low (<0.3 micromol/L) in both groups, but higher among malaria cases (0.19 vs. 0.15 micromol/L). Plasma retinol among the controls showed highly significant positive correlations with individual DDT compounds, particularly with p,p'-DDT (r=0.51, p<0.001). Plasma alpha-tocopherol and beta-carotene seemed not to be affected by DDT residues.

Organochlorine pesticide residues in human milk of a Hmong hill tribe living in Northern Thailand.

In December 1998 whole breast milk samples from 25 Hmong mothers living in the village of Mae Sa Mai, 40 km north of Chiang Mai City, Northern Thailand, were collected and analysed for DDT, heptachlor, HCB and HCH residues (fat normalized data). Short questionnaires and anthropometric measurements were used to obtain information on personal characteristics, lifestyle, contact with pesticides, dietary habits and former residences. DDT was detected in all samples with a median and maximum level of 209 and 2012 ng of total DDT isomers per millilitre of milk, respectively. The median and highest percentages of p,p'-DDT were 23.2 and 44.7%. In 15 samples heptachlor was detected in the metabolized form of heptachlor-epoxide with a median value of 4.4 ng/ml. The estimated daily intakes of DDT, heptachlor and heptachlor-epoxide by the infants exceeded up to 20 times the acceptable daily intakes as recommended by the FAO and WHO. In nine samples HCB was detected with a median value of 5.4 ng/ml from which seven of the nine also had the highest values of DDT residues. The gamma-isomer of HCH was only found in one sample with 3.6 ng/ml. The mean sum-DDT residues with 14.96 mg/kg milk fat, as well as the estimated daily intakes by the infants are one of the highest reported in the 1990s. The fact that the mother breast-feeds her first child and that she originally comes from a region where DDT is still in use as a vector control agent, as well as the former use of organochlorine pesticides (OCPs) in agriculture, seem to be the main factors for high DDT and other OCP residues in the mothers' milk.

Oxidative stress markers and micronutrients in maternal and cord blood in relation to neonatal outcome.

BACKGROUND/OBJECTIVES: Oxidative stress and micronutrient deficiencies have been related to lower birth weight (BW), small for gestational age (SGA) offspring and preterm delivery. SUBJECTS/METHODS: The relation between neonatal outcome (BW, head circumference, SGA, preterm delivery) with markers of oxidative stress and micronutrients in maternal and cord blood was to be examined. Oxidative stress markers (protein carbonyls (PrCarb), 3-nitrotyrosine (3NT), malondialdehyde (MDA)), total protein concentration and lipid-soluble micronutrients (carotenoids, retinol, tocopherols) were measured in 200 newborns (11% preterms, 13% SGA) and 151 mothers. Associations between target parameters in cord plasma and maternal serum with BW, head circumference and risk of being SGA or preterm were explored. RESULTS: Maternal protein concentration, PrCarb, MDA and all lipid-soluble micronutrients were significantly higher compared with newborns, except for 3NT, which was significantly elevated in newborns. Newborn parameters correlated positively with those of mothers. Preterms had lower proteins and retinol but higher PrCarb than terms. Maternal PrCarb and retinol were inversely associated with BW and head circumference. Mothers with PrCarb, MDA and retinol in the highest quintile had a 3.3-fold (0.9; 12.1), 2.1-fold (0.7; 6.4) and 3.3-fold (1.2; 9.4) risk, respectively, for delivering an SGA newborn, whereas the lowest quintile of retinol in cord blood was associated with an increased risk for preterm delivery. CONCLUSIONS: Oxidative stress (elevated PrCarb) was associated with lower BW/head circumference and SGA. Inadequate hemodilution may explain the inverse relation of maternal retinol with BW and head circumference, and the association between highest maternal retinol and risk for SGA.

5-Methyltetrahydrofolate and thiamine diphosphate in cord-blood erythrocytes of preterm versus term newborns.

BACKGROUND/OBJECTIVES: A low folate or low thiamine status may be associated with the risk of preterm delivery, small for gestational age (SGA) offspring and adverse pregnancy outcomes. SUBJECTS/METHODS: 5-Methyltetrahydrofolate (5MTHF) and thiamine diphosphate (TDP) were measured directly in cord-blood erythrocytes (CBEs) of early preterm (n=26; <32 weeks gestational age; including 50% multiple births), late preterm (n=38; 32 to <37 weeks; including 24% multiple births) and term newborns (n=60, 37-42 weeks) via high-performance liquid chromatography and fluorescence detection. Associations between 5MTHF and TDP with gestational age, newborn anthropometrics (birth weight, newborn's length and head circumference) and risk of being SGA were explored. RESULTS: Group comparison as well as multivariate linear regression analysis of cord-blood vitamins revealed that 5MTHF was significantly lower in late preterms compared with terms but did not differ between singletons and multiples. TDP tended to be higher in preterms than in terms and lower in multiples than in singletons in both early and late preterms. Multivariate analysis on birth outcomes showed that 5MTHF was significantly positively associated with gestational age, birth weight and newborn's length. 5MTHF, increasing gestational age and parity were associated with a significantly reduced risk for being SGA, while TDP, multiple births and gender were not associated with the risk for being SGA. CONCLUSIONS: Higher CBE concentrations of 5MTHF were associated with improved birth outcomes. Lower TDP concentrations were observed in multiple births. Future studies evaluating cord-blood vitamin concentrations and their associations with birth outcomes should additionally include dietary intakes and maternal blood concentrations at different stages of pregnancy.