Internet cigarette vendors before and after the credit card and shipping bans.

<p>Distribution of new vs. existing Internet cigarette vendors before and after the credit card and shipping bans, 2004–2007.</p

Internet cigarette vendor attrition over time, 2004–2007.

<p>Proportion of vendors identified a year earlier whose websites were no longer in operation (1/2006 values represent attrition of sites identified 1/2005, before the bans were implemented).</p

Visitor traffic for 50 most popular Internet cigarette vendor websites, adjusted for Internet traffic growth.

<p>Average predicted traffic for the 50 most popular Internet cigarette vendor websites, adjusted for Internet traffic growth (March 2004 to January 2007).</p

Visitor traffic 2004–2007 for 50 most popular Internet cigarette vendor websites.

<p>Average number of unique visitors from March 2004 to January 2007 for the 50 Internet cigarette vendor websites which were most popular in January 2005. Not all of the websites which were most popular in January 2005 were in business in March 2004. Sites were counted as missing data until they started receiving traffic.</p

Advertised payment and shipping practices of Internet cigarette vendors before and after the 2005 credit card and shipping bans.^*

<p>*The credit card ban was implemented in March 2005 and the shipping ban in November 2005.</p><p>**Refers to 50 most popular vendors in January 2005, which were used for the ICV website traffic analysis. 13 of these vendors were new to the sample in January 2005, and by January 2006, 14 of the top 50 vendors had gone out of business.</p>†<p>Denotes banned payment or shipping methods.</p>††<p>The number of vendors shipping via USPS includes vendors shipping via international postal services which would ultimately be delivered in the US by USPS.</p

Descriptive Statistics for Baseline Covariates by Gender and Age-Group, China Health and Nutrition Survey.

<p>*Overweight and obesity classified using the Asian cut-point (BMI ≥ 23 kg/m²) and underweight classified as BMI<18.5 kg/m²[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116190#pone.0116190.ref020" target="_blank">20</a>]</p><p>**Wave at study entry varies by design of this household-based survey, with study entry due to family formation and childbirth and due to exogenous weather shocks and subsequent replacement enrollment of new villages with identical sampling techniques.</p><p>***Eligibility for inclusion in the analysis sample was based on each individual having data from at least two anthropometric visits, thus the latest year for study entry was 2006</p><p>Descriptive Statistics for Baseline Covariates by Gender and Age-Group, China Health and Nutrition Survey.</p

Derived weight trajectories by sex, across three age strata, China Health and Nutrition Survey.

<p>Derived weight trajectories are for the 18 year study period. Each age-sex stratum includes a different set of trajectory classes specific to the within-strata weight trajectories. Separate colors indicate each weight trajectory class, with percent of sample in each class for each sex-age strata shown above each figure.</p

Trajectory Descriptions, Median Posterior Probabilities and Group Membership Percentage, China Health and Nutrition Survey^*.

<p>* Weight change trajectories identified through latent class trajectory modeling with the TRAJ procedure using the censored normal model; individuals were assigned to the class with the highest posterior probability.</p><p>Trajectory Descriptions, Median Posterior Probabilities and Group Membership Percentage, China Health and Nutrition Survey^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116190#t002fn001" target="_blank">*</a>}.</p

Odds Ratios and 95% Confidence Intervals for Baseline Covariates Related to Trajectory Membership, China Health and Nutrition Survey.

<p>* p<0.05</p><p>** p<0.001</p><p>***p<0.0001</p><p>† Baseline BMI status as a three category variable (underweight, normal weight [referent], overweight/obese), and a dichotomous baseline urban-rural variable (referent: urban), age is scaled by a factor of 10 such that OR's represent change in odds with each decade increase in age, and year of study entry as a continuous variable.</p><p>††Reference groups for weight change trajectories were chosen on the basis of a pattern indicating “minimal weight change.”</p><p>Odds Ratios and 95% Confidence Intervals for Baseline Covariates Related to Trajectory Membership, China Health and Nutrition Survey.</p

Linear regression of age-adjusted maternal race on blood metal levels (Beta coefficient and 95% CI).

<p>NHW served as the referent group.</p>*<p>p<0.05;</p>**<p>P<0.001;</p><p>Metal levels were log-transformed.</p