Many studies have examined the negative impact on smartphone addiction in adolescents. Recent concerns have focused on predictors of smartphone addiction. This study aimed to investigate the association of adolescents’ smartphone addiction with family environment (specifically, domestic violence and parental addiction). We further investigated whether self-control and friendship quality, as predictors of smartphone addiction, may reduce the observed risk. We used the 2013 national survey on internet usage and utilization data from the National Information Agency of Korea. Information on exposure and covariates included self-reported experience of domestic violence and parental addiction, sociodemographic variables, and other variables potentially related to smartphone addiction. Smartphone addiction was estimated using a smartphone addiction proneness scale, a standardized measure developed by national institutions in Korea. Adolescents who had experienced domestic violence (OR = 1.74; 95% CI: 1.23–2.45) and parental addiction (OR = 2.01; 95% CI: 1.24–3.27) were found to be at an increased risk for smartphone addiction after controlling for all potential variables. Furthermore, on classifying adolescents according to their level of self-control and friendship quality the association between domestic violence and parental addiction, and smartphone addiction was found to be significant in the group with adolescents with lower levels of self-control (OR = 2.87; 95% CI: 1.68–4.90 and OR = 1.95; 95% CI: 1.34–2.83) and friendship quality (OR = 2.33; 95% CI: 1.41–3.85 and OR = 1.83; 95% CI: 1.26–2.64). Our findings suggest that family dysfunction was significantly associated with smartphone addiction. We also observed that self-control and friendship quality act as protective factors against adolescents’ smartphone addiction.

Background and aims: The smartphone is one of the most popular devices, with the average smartphone usage at 162 min/day and the average length of phone usage at 15.79 hr/week. Although significant concerns have been made about the health effects of smartphone addiction, the relationship between smartphone addiction and accidents has rarely been studied. We examined the association between smartphone addiction and accidents among South Korean university students. Methods: A total of 608 college students completed an online survey that included their experience of accidents (total number; traffic accidents; falls/slips; bumps/collisions; being trapped in the subway, impalement, cuts, and exit wounds; and burns or electric shocks), their use of smartphone, the type of smartphone content they most frequently used, and other variables of interests. Smartphone addiction was estimated using Smartphone Addiction Proneness Scale, a standardized measure developed by the National Institution in Korea. Results: Compared with normal users, participants who were addicted to smartphones were more likely to have experienced any accidents (OR = 1.90, 95% CI: 1.26–2.86), falling from height/slipping (OR = 2.08, 95% CI: 1.10–3.91), and bumps/collisions (OR = 1.83, 95% CI: 1.16–2.87). The proportion of participants who used their smartphones mainly for entertainment was significantly high in both the accident (38.76%) and smartphone addiction (36.40%) groups. Discussion and conclusions: We suggest that smartphone addiction was significantly associated with total accident, falling/slipping, and bumps/collisions. This finding highlighted the need for increased awareness of the risk of accidents with smartphone addiction.

Cadmium, a ubiquitous environmental pollutant, exhibits potential neurotoxic risk. Although compelling evidence suggests cadmium accumulation has a role in the formation of amyloid-β plaques and neurofibrillary tangles, which are the hallmarks of Alzheimer's disease (AD) pathogenesis, the supporting evidence in humans is limited and conflicting. In this study, we investigated the association between blood cadmium levels and AD mortality among older adults by analyzing the prospective data from the 1999–2004 Third National Health and Nutrition Examination Survey (NHANES) and the Linked Mortality File. The data were obtained from the 1999–2004 NHANES and the NHANES (1999–2004) Linked Mortality File. A total of 4,064 participants aged ≥60 years old with available blood cadmium data and no other missing information on their questionnaires at baseline were included in this study. AD was denoted as G30 based on the ICD-10 underlying causes of death. Of the 4,064 participants, 51 subjects died as a result of AD. Compared with participants with low blood cadmium levels (≤0.3 μg/L), those with high cadmium levels (>0.6 μg/L) exhibited a 3.83-fold (hazard ratio = 3.83; 95 % CI = 1.39–10.59) increased risk of AD mortality. In the Kaplan–Meier survival curves for cumulative AD mortality, higher levels of blood cadmium showed marginally significant association with increased mortality at baseline and in patients over 60 years of age (p = 0.0684). We observed a significant association between blood cadmium levels and AD mortality among older adults in the US. Our findings suggest that environmental exposure to cadmium may be a risk factor for AD.

Lead and cadmium are known to be potential female reproductive toxins. However, studies on the relationship between these metals and infertility are limited. This study examines the association between self-reported infertility and blood lead and cadmium levels in US women by comparing metal levels in infertile and pregnant women. Data on blood lead, blood cadmium, and infertility from women aged 20–39 years who participated in the 2013–2014 and 2015–2016 National Health and Nutrition Examination Surveys were analyzed (n = 124, ‘pregnant’ n = 42, ‘infertile’ n = 82). Blood lead and cadmium levels were measured using inductively coupled plasma mass spectrometry, and infertility and pregnancy status were assessed using a self-reported questionnaire. Low blood lead and cadmium levels (geometric mean of blood lead = 0.50 µg/dL and blood cadmium = 0.26 µg/L) were positively associated with self-reported infertility after adjusting for confounding effects (odds ratio (OR) for lead per two-fold increase in blood metal levels = 2.60; 95% confidence interval (95% CI), 1.05–6.41 and OR for cadmium per two-fold increase = 1.84; 95% CI, 1.07–3.15). Although our findings require confirmation, they suggest that even low blood cadmium and lead levels may be deleterious to female fecundity.