The rhizosphere is a complex environment where roots interact with physical, chemical and biological properties of soil. Structural and functional characteristics of roots contribute to rhizosphere ...processes and both have significant influence on the capacity of roots to acquire nutrients. Roots also interact extensively with soil microorganisms which further impact on plant nutrition either directly, by influencing nutrient availability and uptake, or indirectly through plant (root) growth promotion. In this paper, features of the rhizosphere that are important for nutrient acquisition from soil are reviewed, with specific emphasis on the characteristics of roots that influence the availability and uptake of phosphorus and nitrogen. The interaction of roots with soil microorganisms, in particular with mycorrhizal fungi and non-symbiotic plant growth promoting rhizobacteria, is also considered in relation to nutrient availability and through the mechanisms that are associated with plant growth promotion.
Background and aims
Social norms towards smoking are a key concept in tobacco control policy and research. However, the influence and strength of different types of social norms on youth smoking ...uptake is unclear. This study aimed to examine, quantify and compare evidence of the longitudinal associations between different types of social norms towards smoking and youth smoking uptake (initiation and escalation).
Methods
Systematic review searching four databases (MEDLINE, EMBASE, PsycInfo, CINAHL) from January 1998 to October 2020. Evidence synthesis via narrative review, meta‐analysis pooling unadjusted associations (initiation only, due to heterogeneity in escalation outcomes) and meta‐regression comparing effect sizes by norm type and study characteristics. Studies included observational prospective cohort studies using survey methodology with youth aged ≤24 years. Measurements included longitudinal associations between descriptive norms (perceived smoking behaviour) and injunctive norms (perceived approval/disapproval of smoking) among social network(s) and subsequent smoking initiation or escalation.
Results
Thirty articles were identified. In the narrative review, smoking initiation (but not escalation) was consistently predicted by two norms: parental and close friend smoking. Associations between smoking uptake and other descriptive norms (smoking among siblings, family/household, partner, peers, adults) and all injunctive norms (perceived approval of smoking among parents, siblings, close friends/peers, partner, teachers, people important to you, the public) were less consistent or inconclusive. In the meta‐analysis pooling unadjusted associations, 17 articles were included (n = 27 767). Smoking initiation was predicted by the following descriptive norms: smoking among parents Odds Ratio (OR) = 1.88, 95% Confidence Interval (CI) = 1.56–2.28, close friends (OR = 2.53, 95% CI = 1.99–3.23), siblings (OR = 2.44, 95% CI = 1.93–3.08), family/household (OR = 1.55, 95% CI = 1.36–1.76) and adults (OR = 1.34, 95% CI = 1.02–1.75), but not peers (OR = 1.14, 95% CI = 0.92–1.42). Smoking initiation was also predicted by two injunctive norms, perceived approval of smoking among parents (OR = 1.74, 95% CI = 1.27–2.38) and the public (OR = 4.57, 95% CI = 3.21–6.49), but not close friends/peers (OR = 2.36, 95% CI = 0.86–6.53) or people important to the individual (OR = 1.24, 95% CI = 0.98–1.58).
Conclusions
In this systematic review (narrative and meta‐analysis), descriptive norms of parents’ and close friends’ smoking behaviour appeared to be consistent predictors of youth smoking initiation, more so than the descriptive norms of more distal social networks and injunctive norms.
To estimate tobacco use prevalence in healthcare workers (HCW) by country income level, occupation and sex, and compare the estimates with the prevalence in the general population.
We systematically ...searched five databases; Medline, EMBASE, CINHAL Plus, CAB Abstracts, and LILACS for original studies published between 2000 and March 2016 without language restriction. All primary studies that reported tobacco use in any category of HCW were included. Study extraction and quality assessment were conducted independently by three reviewers, using a standardised data extraction and quality appraisal form. We performed random effect meta-analyses to obtain prevalence estimates by World Bank (WB) country income level, sex, and occupation. Data on prevalence of tobacco use in the general population were obtained from the World Health Organisation (WHO) Global Health Observatory website. The review protocol registration number on PROSPERO is CRD42016041231.
229 studies met our inclusion criteria, representing 457,415 HCW and 63 countries: 29 high-income countries (HIC), 21 upper-middle-income countries (UMIC), and 13 lower-middle-and-low-income countries (LMLIC). The overall pooled prevalence of tobacco use in HCW was 21%, 31% in males and 17% in females. Highest estimates were in male doctors in UMIC and LMLIC, 35% and 45%, and female nurses in HIC and UMIC, 21% and 25%. Heterogeneity was high (I2 > 90%). Country level comparison suggest that in HIC male HCW tend to have lower prevalence compared with males in the general population while in females the estimates were similar. Male and female HCW in UMIC and LMLIC tend to have similar or higher prevalence rates relative to their counterparts in the general population.
HCW continue to use tobacco at high rates. Tackling HCW tobacco use requires urgent action as they are at the front line for tackling tobacco use in their patients.
Aims
This paper provides a concise review of the efficacy, effectiveness and affordability of health‐care interventions to promote and assist tobacco cessation, in order to inform national guideline ...development and assist countries in planning their provision of tobacco cessation support.
Methods
Cochrane reviews of randomized controlled trials (RCTs) of major health‐care tobacco cessation interventions were used to derive efficacy estimates in terms of percentage‐point increases relative to comparison conditions in 6–12‐month continuous abstinence rates. This was combined with analysis and evidence from ‘real world’ studies to form a judgement on the probable effectiveness of each intervention in different settings. The affordability of each intervention was assessed for exemplar countries in each World Bank income category (low, lower middle, upper middle, high). Based on World Health Organization (WHO) criteria, an intervention was judged as affordable for a given income category if the estimated extra cost of saving a life‐year was less than or equal to the per‐capita gross domestic product for that category of country.
Results
Brief advice from a health‐care worker given opportunistically to smokers attending health‐care services can promote smoking cessation, and is affordable for countries in all World Bank income categories (i.e. globally). Proactive telephone support, automated text messaging programmes and printed self‐help materials can assist smokers wanting help with a quit attempt and are affordable globally. Multi‐session, face‐to‐face behavioural support can increase quit success for cigarettes and smokeless tobacco and is affordable in middle‐ and high‐income countries. Nicotine replacement therapy, bupropion, nortriptyline, varenicline and cytisine can all aid quitting smoking when given with at least some behavioural support; of these, cytisine and nortriptyline are affordable globally.
Conclusions
Brief advice from a health‐care worker, telephone helplines, automated text messaging, printed self‐help materials, cytisine and nortriptyline are globally affordable health‐care interventions to promote and assist smoking cessation. Evidence on smokeless tobacco cessation suggests that face‐to‐face behavioural support and varenicline can promote cessation.
To reduce inequalities between individuals with and without mental health problems, a better understanding is required of triggers and success of quit attempts among the third of smokers with mental ...health problems. The aim was to assess whether there are differences by mental health status in (i) triggers for quit attempts, (ii) use of evidence-based support (iii) and quit success.
Monthly cross-sectional household surveys of representative samples of the adult population in England. In 2016/2017, 40,831 adults were surveyed; 1956 who had attempted to stop smoking cigarettes in the past year were included. Logistic regressions assessed associations between mental health (ever diagnosis, past-year treatment, past-month distress), triggers, support used and quit success, adjusting for sociodemographic and smoking characteristics.
Concern about future health, current health problems and expense of smoking were the most common triggers overall. For respondents with an ever diagnosis, past-year treatment or serious past-month distress, quit attempts were more frequently triggered by current health problems. Non-evidence-based support and e-cigarettes were used most often, and this did not differ by mental health status. Respondents with an ever diagnosis and moderate or serious distress were less likely to have used non-prescription nicotine replacement therapy (NRT). Respondents with past-year treatment or serious distress were more likely to have used prescription medication/behavioural support. Quit success did not differ by mental health status. Compared with non-evidence-based support, non-prescription NRT conferred no benefit. There was some evidence that prescription medication/behavioural support was beneficial (depending on outcome and adjustment, ORs ranged from 1.46, 95% CI 0.92-2.31, to 1.69, 1.01-2.86). E-cigarettes were associated with higher success rates after adjustment for different indicators of mental health (ORs ranged from 2.21, 1.64-2.98, to 2.25, 1.59-3.18).
Smokers with mental health problems were more likely to have attempted to quit because of health problems and were more likely to have used gold standard support (medication and behavioural support) than other smokers. E-cigarettes were strongly associated with increased success and were used similarly by those with and without mental health problems, indicating that improved uptake of e-cigarettes for smoking cessation among smokers with mental health problems could help address inequalities.
Tobacco control strategies have engendered overall declines in smoking; however, a large gap remains between people with and without mental health problems, causing substantial health inequalities. ...Population-level information on barriers and opportunities for improvements is scarce. We aimed to assess mental health status of cigarette smokers and recent ex-smokers ('past-year smokers') in England, and smoking and harm reduction behaviour and quit attempts by mental health status.
Data were collected from 5637 current and 434 recent ex-smokers in 2016/17 in household surveys of representative samples of adults. We calculated weighted prevalence of different indicators of mental health problem: a) ever diagnosis, b) none, moderate, serious past-month distress, c) past-year treatment. We compared weighted smoking status, cigarette type, dependence, motivation to stop smoking, cutting down, use of nicotine replacement therapy or e-cigarettes, short-term abstinence, and quit attempts according to mental health status.
Among past-year smokers: 35.9% ever had a diagnosis; 24.3% had experienced moderate, an additional 9.7% serious, past-month distress; 21.9% had had past-year treatment. Those with an indication of a mental health problem were more highly dependent and more likely to smoke roll-your-own cigarettes but also more likely to be motivated to stop smoking, to cut down, use nicotine replacement therapy or e-cigarettes and to have attempted to quit in the past year.
About a third of cigarette smokers in England have mental health problems. Interventions should address their increased dependence and leverage higher prevalence of harm reduction behaviours, motivation to stop and attempts to stop smoking.
COVID-19 is primarily a respiratory illness, and smoking adversely impacts the respiratory and immune systems; this confluence may therefore incentivize smokers to quit. The present study, conducted ...in four high-income countries during the first global wave of COVID-19, examined the association between COVID-19 and: (1) thoughts about quitting smoking; (2) changes in smoking (quit attempt, reduced or increased smoking, or no change); and (3) factors related to a positive change (making a quit attempt or reducing smoking) based on an adapted framework of the Health Belief Model.
This cross-sectional study included 6870 adult smokers participating in the Wave 3 (2020) ITC Four Country Smoking and Vaping Survey conducted in Australia, Canada, England, and United States (US). These four countries had varying responses to the pandemic by governments and public health, ranging from advising voluntary social distancing to implementing national and subnational staged lockdowns. Considering these varying responses, and the differences in the number of confirmed cases and deaths (greatest in England and the US and lowest in Australia), smoking behaviours related to COVID-19 may have differed between countries. Other factors that may be related to changes in smoking because of COVID-19 were also explored (e.g., sociodemographics, nicotine dependence, perceptions about personal and general risks of smoking on COVID-19). Regression analyses were conducted on weighted data.
Overall, 46.7% of smokers reported thinking about quitting because of COVID-19, which differed by country (p<0.001): England highest (50.9%) and Australia lowest (37.6%). Thinking about quitting smoking because of COVID-19 was more frequent among: females, ethnic minorities, those with financial stress, current vapers, less dependent smokers (non-daily and fewer cigarettes smoked/day), those with greater concern about personal susceptibility of infection, and those who believe COVID-19 is more severe for smokers. Smoking behaviour changes due to COVID-19 were: 1.1% attempted to quit, 14.2% reduced smoking, and 14.6% increased smoking (70.2% reported no change). Positive behaviour change (tried to quit/reduced smoking) was reported by 15.5% of smokers, which differed by country (p = 0.02), where Australia had significantly lower rates than the other three countries. A positive behavioural smoking change was more likely among smokers with: lower dependence, greater concern about personal susceptibility to infection, and believing that COVID-19 is more severe for smokers.
Though nearly half of smokers reported thinking about quitting because of COVID-19, the vast majority did not change their smoking behaviour. Smokers were more likely to try and quit or reduce their smoking if they had greater concern about susceptibility and severity of COVID-19 related to smoking. Smokers in Australia were least likely to reduce or try to quit smoking, which could be related to the significantly lower impact of COVID-19 during the early phase of the pandemic relative to the other countries.
Aim
To describe the methods of the 2016 International Tobacco Control (ITC) Four Country Smoking and Vaping (4CV) Survey, conducted in 2016 in Australia (AU), Canada (CA), England (EN) and the United ...States (US).
Methods
The respondents were cigarette smokers, former smokers (quit within the previous 2 years), and at‐least‐weekly vapers, aged 18 years and older. Eligible cohort members from the ITC Four Country Survey (4C) were retained. New respondents were sampled by commercial firms from their panels. Where possible, ages 18–24 and vapers were oversampled. Data were collected online, and respondents were remunerated. Survey weights were calibrated to benchmarks from nationally representative surveys.
Results
Response rates by country for new recruits once invited ranged from 15.2 to 49.6%. Sample sizes for smokers/former smokers were 1504 in AU, 3006 in CA, 3773 in EN and 2239 in the US. Sample sizes for additional vapers were 727 in CA, 551 in EN and 494 in the US.
Conclusion
The International Tobacco Control Four Country Smoking and Vaping Survey design and data collection methods allow analyses to examine prospectively the use of cigarettes and nicotine vaping products in jurisdictions with different regulatory policies. The effects on the sampling designs and response quality of recruiting the respondents from commercial panels are mitigated by the use of demographic and geographic quotas in sampling; by quality control measures; and by the construction of survey weights taking into account smoking/vaping status, sex, age, education and geography.
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