Environmental exposure to lead remains a public health problem. Although lead exposure has decreased in the last couple of decades,¹ x 1 NTP. NTP Monograph on Health Effects of Low-Level Lead National Toxicology Program. US Department of Health and Human Services, ; 2012 ( https://ntp.niehs.nih.gov/ntp/ohat/lead/final/monographhealtheffectslowlevellead_newissn_508.pdf. Accessed April 5, 2018.) Google Scholar See all References ^{, 2} x 2 Skerfving, S. and Bergdahl, I. Lead. in: G. Nordberg, B. Fowler, M.E. Nordberg (Eds.) Handbook on the Toxicology of Metals. Elsevier Science, Amsterdam, The Netherlands; 2015 Crossref | Scopus (13) | Google Scholar See all References there is evidence of health effects in children and adults even at low lead levels.¹ x 1 NTP. NTP Monograph on Health Effects of Low-Level Lead National Toxicology Program. US Department of Health and Human Services, ; 2012 ( https://ntp.niehs.nih.gov/ntp/ohat/lead/final/monographhealtheffectslowlevellead_newissn_508.pdf. Accessed April 5, 2018.) Google Scholar See all References Exposure occurs through ingestion of contaminated food, drinking water, and dust, as well as smoking and inhalation of polluted air in areas with heavy traffic or industrial emissions.² x 2 Skerfving, S. and Bergdahl, I. Lead. in: G. Nordberg, B. Fowler, M.E. Nordberg (Eds.) Handbook on the Toxicology of Metals. Elsevier Science, Amsterdam, The Netherlands; 2015 Crossref | Scopus (13) | Google Scholar See all References ^{, 3} x 3 EFSA. EFSA Panel on Contaminants in the Food Chain (CONTAM); scientific opinion on lead in food. EFSA J. 2010; 8: 151 Google Scholar See all References The most important dietary contributors in the United States and Europe are cereals, leafy vegetables, potatoes, and tap water.³ x 3 EFSA. EFSA Panel on Contaminants in the Food Chain (CONTAM); scientific opinion on lead in food. EFSA J. 2010; 8: 151 Google Scholar See all References More than 90% of absorbed lead is stored in bones,² x 2 Skerfving, S. and Bergdahl, I. Lead. in: G. Nordberg, B. Fowler, M.E. Nordberg (Eds.) Handbook on the Toxicology of Metals. Elsevier Science, Amsterdam, The Netherlands; 2015 Crossref | Scopus (13) | Google Scholar See all References ^{, 4} x 4 Barry, P.S. A comparison of concentrations of lead in human tissues. Br J Ind Med. 1975; 32: 119–139 PubMed | Google Scholar See all References ^{, 5} x 5 Silbergeld, E.K., Sauk, J., Somerman, M. et al. Lead in bone: storage site, exposure source, and target organ. Neurotoxicology. 1993; 14: 225–236 PubMed | Google Scholar See all References so bone lead level reflects long-term exposure and body burden. Lead in blood reflects more recent exposure, but also whole-body burden, and is the most commonly used biomarker of lead exposure.² x 2 Skerfving, S. and Bergdahl, I. Lead. in: G. Nordberg, B. Fowler, M.E. Nordberg (Eds.) Handbook on the Toxicology of Metals. Elsevier Science, Amsterdam, The Netherlands; 2015 Crossref | Scopus (13) | Google Scholar See all References ^{, 6} x 6 Barbosa, F. Jr., Tanus-Santos, J.E., Gerlach, R.F., and Parsons, P.J. A critical review of biomarkers used for monitoring human exposure to lead: advantages, limitations, and future needs. Environ Health Perspect. 2005; 113: 1669–1674 Crossref | PubMed | Scopus (319) | Google Scholar See all References

To explore definitions for multisite pain, and compare associations with risk factors for different patterns of musculoskeletal pain, we analysed cross-sectional data from the Cultural and Psychosocial Influences on Disability (CUPID) study. The study sample comprised 12,410 adults aged 20-59 years from 47 occupational groups in 18 countries. A standardised questionnaire was used to collect information about pain in the past month at each of 10 anatomical sites, and about potential risk factors. Associations with pain outcomes were assessed by Poisson regression, and characterised by prevalence rate ratios (PRRs). Extensive pain, affecting 6-10 anatomical sites, was reported much more frequently than would be expected if the occurrence of pain at each site were independent (674 participants vs 41.9 expected). In comparison with pain involving only 1-3 sites, it showed much stronger associations (relative to no pain) with risk factors such as female sex (PRR 1.6 vs 1.1), older age (PRR 2.6 vs 1.1), somatising tendency (PRR 4.6 vs 1.3), and exposure to multiple physically stressing occupational activities (PRR 5.0 vs 1.4). After adjustment for number of sites with pain, these risk factors showed no additional association with a distribution of pain that was widespread according to the frequently used American College of Rheumatology criteria. Our analysis supports the classification of pain at multiple anatomical sites simply by the number of sites affected, and suggests that extensive pain differs importantly in its associations with risk factors from pain that is limited to only a small number of anatomical sites.

To compare the prevalence of disabling low back pain (DLBP) and disabling wrist/hand pain (DWHP) among groups of workers carrying out similar physical activities in different cultural environments, and to explore explanations for observed differences, we conducted a cross-sectional survey in 18 countries. Standardised questionnaires were used to ascertain pain that interfered with everyday activities and exposure to possible risk factors in 12,426 participants from 47 occupational groups (mostly nurses and office workers). Associations with risk factors were assessed by Poisson regression. The 1-month prevalence of DLBP in nurses varied from 9.6% to 42.6%, and that of DWHP in office workers from 2.2% to 31.6%. Rates of disabling pain at the 2 anatomical sites covaried (r = 0.76), but DLBP tended to be relatively more common in nurses and DWHP in office workers. Established risk factors such as occupational physical activities, psychosocial aspects of work, and tendency to somatise were confirmed, and associations were found also with adverse health beliefs and group awareness of people outside work with musculoskeletal pain. However, after allowance for these risk factors, an up-to 8-fold difference in prevalence remained. Systems of compensation for work-related illness and financial support for health-related incapacity for work appeared to have little influence on the occurrence of symptoms. Our findings indicate large international variation in the prevalence of disabling forearm and back pain among occupational groups carrying out similar tasks, which is only partially explained by the personal and socioeconomic risk factors that were analysed.

Lithium, used for treating bipolar disease, crosses freely the placenta and is classified as teratogenic. It is unclear to what extent environmental lithium exposure may affect fetal growth and development. To elucidate potential effects of lithium exposure through drinking water during pregnancy on fetal size. We developed a prospective population-based mother-child cohort (N=194) in an area with highly varying drinking water lithium concentrations (5-1600 μg/L) in northern Argentinean Andes. Blood and urinary lithium concentrations (sampled repeatedly during pregnancy) were measured using inductively coupled plasma mass spectrometry. We measured fetal size by ultrasound in second and third trimesters, and weight, length and head circumference at birth. Multivariable models were used to examine associations between lithium exposure (continuous and in tertiles) and fetal size measures. Lithium in maternal blood (median 25; range 1.9-145 μg/L) and urine (1645; 105-4600 μg/L) was inversely associated (apparently linearly) with all fetal measures (body, head and femur) in the second trimester, and with birth length (β -0.53 cm per 25 μg/L increase in blood lithium, 95%CI -1.0; -0.052). An increase of 100 μg/L in blood was associated with 2 cm shorter newborns (about one standard deviation). Lithium exposure through drinking water was associated with impaired fetal size and this seemed to be initiated in early gestation. Further studies are warranted to confirm causality and to understand the mechanisms. If confirmed, these findings have public health relevance and emphasize the need for more data on lithium concentrations in drinking water, including bottled water.