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Abstract: Aims: To conduct a systematic review and meta‐analysis of studies in order to estimate the effect of US medical marijuana laws (MMLs) on past‐month marijuana use prevalence among adolescents. Methods: A total of 2999 papers from 17 literature sources were screened systematically. Eleven studies, developed from four ongoing large national surveys, were meta‐analyzed. Estimates of MML effects on any past‐month marijuana use prevalence from included studies were obtained from comparisons of pre–post MML changes in MML states to changes in non‐MML states over comparable time‐periods. These estimates were standardized and entered into a meta‐analysis model with fixed‐effects for each study. Heterogeneity among the study estimates by national data survey was tested with an omnibus F‐test. Estimates of effects on additional marijuana outcomes, of MML provisions (e.g. dispensaries) and among demographic subgroups were abstracted and summarized. Key methodological and modeling characteristics were also described. Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines were followed. Results: None of the 11 studies found significant estimates of pre–post MML changes compared with contemporaneous changes in non‐MML states for marijuana use prevalence among adolescents. The meta‐analysis yielded a non‐significant pooled estimate (standardized mean difference) of −0.003 (95% confidence interval = −0.012, +0.007). Four studies compared MML with non‐MML states on pre‐MML differences and all found higher rates of past‐month marijuana use in MML states pre‐MML passage. Additional tests of specific MML provisions, of MML effects on additional marijuana outcomes and among subgroups generally yielded non‐significant results, although limited heterogeneity may warrant further study. Conclusions: Synthesis of the current evidence does not support the hypothesis that US medical marijuana laws (MMLs) until 2014 have led to increases in adolescent marijuana use prevalence. Limited heterogeneity exists among estimates of effects of MMLs on other patterns of marijuana use, of effects within particular population subgroups and of effects of specific MML provisions. [ABSTRACT FROM AUTHOR]

Over the past two decades, research on pediatric bipolar disorder has grown geometrically. The diagnosis of pediatric bipolar disorder was met with enthusiasm, which in healthy doses catalyzed change, and skepticism, which in good measure pushes for rigor. Skepticism led to productive questions about the phenomenology of pediatric bipolar disorder and how best to diagnose and treat it. With regard to prevalence, key questions included whether it was increasing over time, and whether it was limited to the United States. In 2011, we published a meta‐analysis addressing the prevalence questions; results indicated that bipolar disorder manifested at statistically indistinguishable rates in youth community samples across the world. In their recent paper, Parry et al. examine the studies included in the 2011 meta‐analysis using a qualitative approach. Their opinion piece represents a step backwards; every study has shortcomings, but in focusing on a dozen individual studies, Parry et al. fail to take into account the preponderance of evidence – literally thousands of articles across countries, cohorts and methodologies – that support the existence of bipolar disorder in both prepubescent youth and adolescents. This commentary addresses misperceptions regarding the diagnosis of bipolar disorder in youth, particularly with regard to cross‐informant agreement, to present converging data from international sources regarding the onset of bipolar disorder in childhood, and to correct the false claim that pediatric bipolar disorder is controversial. As clinicians and researchers, we have an obligation to do what we can to improve the lives of youth affected by mental illness. Denying the existence of a serious mood disorder will not serve the best interests of young people and will perpetuate the long delays many experience before getting an accurate diagnosis, appropriate treatment, and a fair chance at a good quality of life. Read the Editors' introduction at: doi: 10.1111/camh.12315 Read the core debate at: doi: 10.1111/camh.12231; doi: 10.1111/camh.12243; doi: 10.1111/camh.12306 Read more perspectives in this debate at: doi: 10.1111/camh.12318 doi: 10.1111/camh.12317; doi: 10.1111/camh.12316; doi: 10.1111/camh.12313; doi: 10.1111/camh.12310; doi: 10.1111/camh.12314 [ABSTRACT FROM AUTHOR]

Aims: This study investigated the association between serum calcium levels and the prevalence of T2D using a cross‐sectional study and Mendelian randomization analysis. Methods: Cross‐sectional data were obtained from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Serum calcium levels were divided into three groups (low, medium and high groups) according to the tertiles. Logistic regression was used to estimate the association between serum calcium levels and T2D prevalence. Instrumental variables for serum calcium levels were obtained from the UK Biobank and a two‐sample MR analysis was performed to examine the causal relationship between genetically predicted serum calcium levels and the risk of T2D. Results: A total of 39,645 participants were available for cross‐sectional analysis. After adjusting for covariates, participants in the high serum calcium group had significantly higher odds of T2D (OR = 1.18, 95% CI = 1.07, 1.30, p = 0.001) than those in the moderate group. Restricted cubic spline plots showed a J‐shaped curve relationship between serum calcium level and prevalence of T2D. Consistently, Mendelian randomization analysis showed that higher genetically predicted serum calcium levels were causally associated with a higher risk of T2D (OR = 1.16, 95% CI: 1.01, 1.33, p = 0.031). Conclusions: The results of this study suggest that higher serum calcium levels are causally associated with a higher risk of T2D. Further studies are needed to clarify whether intervening in high serum calcium could reduce the risk of T2D. [ABSTRACT FROM AUTHOR]

Objective: To better understand the epidemiology of preterm birth among Pacific Islanders in the United States and the US‐Affiliated Pacific Islands. Methods: Systematic searches of MEDLINE, Embase, CINAHL, PsycINFO, two nonindexed regional journals, and gray literature were conducted and finalized in September 2021. Observational studies published since January 2010 that documented preterm birth outcomes among Pacific Islanders in the United States and the US‐Affiliated Pacific Islands were eligible for inclusion. Outcomes of interest included preterm birth prevalence, risk compared with white women, and risk factors for preterm birth among Pacific Islanders. Results: Fourteen of the 3183 screened articles were included in meta‐analyses. Random‐effects models were used for pooled estimates with 95% confidence intervals. The pooled prevalence of preterm birth among Pacific Islanders was 11.2%, 95% CI: 9.3%‐13.6%. Marshallese women had the highest pooled prevalence (20.7%, 95% CI 18.6%‐23.0%) among Pacific Islander subgroups. Compared with white women, Pacific Islander women had higher odds of experiencing preterm birth (OR = 1.40, 95% CI: 1.28‐1.53). Four risk factors for preterm birth could be explored with the data available: hypertension, diabetes, smoking, and pre‐pregnancy body mass index; hypertension and diabetes significantly increased the odds of preterm birth. Conclusions: Existing literature suggests that United States Pacific Islanders were more likely to experience preterm birth than white women, although the pooled prevalence varied by Pacific Islander subgroup. Data support the need for disaggregation of Pacific Islanders in future research and argue for examination of subgroup‐specific outcomes to address perinatal health disparities. [ABSTRACT FROM AUTHOR]

Pregnant women and newborns are at increased risk of vitamin D deficiency. Our objective was to create a global summary of maternal and newborn vitamin D status. We completed a systematic review (1959–2014) and meta‐analysis of studies reporting serum 25‐hydroxyvitamin D [25(OH)D] concentration in maternal and newborn populations. The 95 identified studies were unevenly distributed by World Health Organization (WHO) region: Americas (24), European (33), Eastern Mediterranean (13), South‐East Asian (7), Western Pacific (16) and African (2). Average maternal 25(OH)D concentrations (nmol L−1) by region were 47–65 (Americas), 15–72 (European), 13–60 (Eastern Mediterranean), 20–52 (South‐East Asian), 42–72 (Western Pacific) and 92 (African). Average newborn 25(OH)D concentrations (nmol L−1) were 35–77 (Americas), 20–50 (European), 5–50 (Eastern Mediterranean), 20–22 (South‐East Asian), 32–67 (Western Pacific) and 27–35 (African). The prevalences of 25(OH)D <50 and <25 nmol L−1 by WHO region in pregnant women were: Americas (64%, 9%), European (57%, 23%), Eastern Mediterranean (46%, 79%), South‐East Asian (87%, not available) and Western Pacific (83%, 13%). Among newborns these values were: Americas (30%, 14%), European (73%, 39%), Eastern Mediterranean (60%, not available), South‐East Asian (96%, 45%) and Western Pacific (54%, 14%). By global region, average 25(OH)D concentration varies threefold in pregnant women and newborns, and prevalence of 25(OH)D <25 nmol L−1 varies eightfold in pregnant women and threefold in newborns. Maternal and newborn 25(OH)D concentrations are highly correlated. Addressing vitamin D deficiency in pregnant women and newborns should be a global priority. To protect children from the adverse effects of vitamin D deficiency requires appropriate interventions during both pregnancy and childhood. [ABSTRACT FROM AUTHOR]

Background This research extends prior epidemiological estimates for the United States and re-examines a previously described male excess in alcohol drinking. Its aim was to estimate fine-grained age-specific incidence of becoming a drinker among 12- to 24-year-old U.S. males and females, and to compare incidence estimates with prevalence proportions. Methods The study population is 12- to 24-year-old noninstitutionalized U.S. civilian residents. Estimates are from 12 successive U.S. National Surveys on Drug Use and Health ( NSDUH), with nationally representative samples drawn each year from 2002 to 2013 and assessed via computer-assisted self-interviews ( n ~ 390,000). Analysis-weighted incidence and prevalence estimates are generated using the NSDUH Restricted Data Analysis System for 6 year-pairs. Meta-analysis-derived summary estimates are provided, treating each year-pair as a replication. Results In this 21st century evidence, there no longer is male excess of incidence with respect to underage drinking. Indeed, in mid-adolescence, there is a clear female excess for the risk of becoming an underage drinker. Meta-analytic summaries disclosed no other male-female differences in incidence. Nevertheless, a male excess in the prevalence of recently active drinking can be seen after the age of 19 years. Conclusions This new evidence from the United States shows that the so-called 'gender gap' in risk of becoming a drinker has narrowed to the point of there being no gap at all. Indeed, in mid-adolescence, risk of starting to drink is greater for females than for males. [ABSTRACT FROM AUTHOR]