Exposure to second hand smoke at home and its associated factors findings from the global adult tobacco use survey in vietnam, 2010 (2)

2012 Abstract Objective The paper describes the pattern of exposure to second-hand smoke SHS at home among the adult pop-ulation of Vietnam and examines associated socio-demo-graphic fac

O R I G I N A L P A P E R

Exposure to second-hand smoke at home and its associated

factors: findings from the Global Adult Tobacco Use survey

in Vietnam, 2010

Hoang Van Minh• Kim Bao Giang•Le Thi Thanh Xuan•

Pham Thi Quynh Nga•Phan Thi Hai• Nguyen Thac Minh•

Nguyen The Quan•Jason Hsia

Received: 5 September 2011 / Accepted: 27 January 2012 / Published online: 29 February 2012

 Springer Science+Business Media B.V 2012

Abstract

Objective The paper describes the pattern of exposure to

second-hand smoke (SHS) at home among the adult

pop-ulation of Vietnam and examines associated

socio-demo-graphic factors

Methods A total of 11,142 households were selected for

this survey using a two-phase sampling design analogous

with three-stage stratified cluster sampling The dependent

variable was the status of exposure to SHS at home

Independent variables included gender, age, occupation,

asset-based wealth quintile, ethnicity, marital status,

resi-dence Logistic regression modelling was performed to

examine the association with relevant factors of patterns of

exposure to second-hand smoke among non-smokers

Results Of adults aged 15 years and above (representing

approximately 47 million people) 73.1% reported they

were exposed to SHS at home at least monthly

Consid-ering non-smokers only, the prevalence of exposure to

SHS at home was 67.6% (equivalent to approximately 33

million non-smokers) The significant correlates of the status of exposure to SHS at home among non-smokers were female gender, ethnic minority, low education, and lack of smoking restriction at home

Conclusion The study showed that a high percentage of people are exposed to second-hand smoke at home Dis-advantaged people were more likely than the better-off to

be exposed to SHS at home

Keywords Second-hand smoke Socio-demographic factors Global Adult Tobacco Use survey  Vietnam

Introduction

Second-hand smoke (SHS) exposure, also known as

‘‘involuntary smoking’’ or ‘‘passive smoking’’, is non-smokers’ inhalation of smoke from the exhalation of smokers or from burning cigarettes [1,2] Evidence of the adverse health effects of exposure to SHS has been accu-mulating for nearly 50 years [3 5] The U.S Surgeon General estimates that living with a smoker increases a non-smoker’s chances of developing lung cancer by 20–30% [1] Research also suggests that second-hand smoke may increase the risk of breast cancer, nasal sinus cavity cancer, and nasopharyngeal cancer in adults, and leukemia, lymphoma, and brain tumours in children [1,2,

6, 7] Exposure to second-hand smoke may increase the risk of non-cancerous conditions, for example chronic coughing, phlegm, and wheezing, chest discomfort, severe lower respiratory tract infections, for example bronchitis or pneumonia, and eye and nose irritation [6,8,9]

Globally, it is estimated that approximately one-third of adults are regularly exposed to second-hand tobacco smoke [10] Second-hand smoke is estimated to cause

H Van Minh (&)  K B Giang  L T T Xuan

Institute for Preventive Medicine and Public Health,

Hanoi Medical University, No 1- Ton That Tung, Dong Da,

Hanoi, Vietnam

e-mail: hvminh71@yahoo.com

P T Q Nga

World Health Organization Office in Vietnam, Hanoi, Vietnam

P T Hai  N T Minh

Vietnam Steering Committee on Smoking and Health

(VINACOSH), Hanoi, Vietnam

N T Quan

General Statistics Office, Hanoi, Vietnam

J Hsia

Center for Disease Control and Prevention, Atlanta, GA, USA

DOI 10.1007/s10552-012-9907-z

approximately 600,000 premature deaths per year

world-wide Of all deaths attributable to second-hand tobacco

smoke, 31% occur among children and 64% occurs among

women [10] In addition to a large and growing health

burden, second-hand smoke exposure also imposes

eco-nomic burdens on individuals and countries, both the direct

costs of health care and indirect costs from reduced

pro-ductivity Several studies estimate that 10% of total

tobacco-related economic costs are attributable to

second-hand smoke exposure [11]

Although smoking prevalence is decreasing in many

high-income countries, it is increasing in many low and

middle-income countries [12] As a result, the amount of

second-hand smoke and its associated burden of disease are

now rising in low and middle-income countries [13] The

burden of morbidity from SHS exposure, as measured by

disability adjusted life years (DALYs), has been shown to

be higher in low-income countries in Southeast Asia and in

the eastern Mediterranean region than in Europe [13]

Disadvantaged people (especially, women and children)

have been suffering more from the burden of disease

caused by second-hand smoke [1,13]

In Vietnam, a low-income country in Southeast Asia,

smoking is the main form of tobacco use and is very

common The prevalence of smoking among those aged

15 years old and over in 2002 was 56.1% among men and

1.8% among women) In 2002, 63% of households had at

least one smoker 71% of children under age 5 lived in

households with at least one smoker [14] In 2003, nearly

60% school-attending youth reported being exposed to

second-hand smoke at home [15]

Although the amount of research on tobacco use in

Vietnam has recently increased rapidly, there remains a

lack of reporting on the pattern of exposure to second-hand

smoke among populations The objectives of this paper are

to describe the pattern of exposure to second-hand smoke

at home among the adult population in Vietnam and to

examine its socio-economic correlates This case study

provides scientific evidence for policy changes and

inter-vention in Vietnam, and in other low and middle-income

countries

Methods

Data source

Data used in this paper were obtained from the Global

Adult Tobacco Survey (GATS) conducted in Vietnam in

2010 The GATS is a household survey (using face-to-face

interviews) that was launched in February 2007 as a new

component of the ongoing Global Tobacco Surveillance

System (GTSS) [16] The GATS in Vietnam was designed

to be a nationally representative survey of all non-institu-tionalized men and women age 15 and older who consid-ered Vietnam to be their primary place of residence

Sample size and sampling

A two-phase sampling design analogous to three-stage stratified cluster sampling was used According to the GATS sample design protocol, to obtain reliable estimates

of key variables for gender and urban/rural areas 8,000 people are required On the basis of previous similar national household surveys, it was assumed that overall ineligibility and non-response would be 35% After taking the response into account, the final total sample size was 11,142 Half of the enumeration areas (EAs) to be sam-pled were then assigned to urban and half to rural Because of the different sizes of urban and rural areas, GATS sampled 18 households from each urban EA and 16 households from each rural EA Therefore a total of 657 EAs were sampled to obtain 11,142 households The sample size for EAs was then proportionally allocated across six strata, on the basis of the total number of households

In 2009, the General Statistics Office (GSO), Vietnam, conducted a population and housing census The GSO also prepared a 15% master sample to serve as a future national survey sampling framework The 15% master sample contains a subset of EAs that consists of 15% of the population in Vietnam stratified by three groups The first group consists of 132 districts, towns, or cities of provinces The second group consists of 294 plain and coastal districts The third group consists of 256 moun-tainous and island districts The GATS sample was drawn from the 15% master sample after further stratification of the three groups into urban and rural areas (six strata in total)

At the first stage of sampling, the primary sampling unit (PSU) was an enumeration area (EA) The sampling framework was a list of the EAs, from the 15% master sample, with the number of households and identifiable information, administered by the GSO, Vietnam, in 2009 from the census For each of the six strata, the designated number of EAs was selected A selection probability pro-portional to size (PPS) sampling method was used, where the size was the probability of selection of an EA, using PPS sampling, from the entire target population divided by the probability of selection of an EA for the master sample

At the second stage of sampling, 18 households from the selected urban EA and 16 households from the selected rural EA were chosen using simple systematic random sampling One eligible household member from each selected household was then randomly chosen for interview

Note that this design and the design in which EAs were

sampled directly from the universe were analogous The

probability of selection of an eligible individual was

cal-culated as the product the of probability of selection for

each stage The sampling base weight for an eligible

individual was the inverse of the probability of selection

shown above

Data collection procedure

Data collection was done by the GSO, under the

co-supervision of the World Health Organization in Vietnam,

Vinacosh, and Hanoi Medical University Twenty-six

data-collection teams were involved in GATS Vietnam 2010

Each team consisted of one team leader and four

inter-viewers to ensure close supervision and collection of high

quality data They had computer skills and previous

experience in conducting of GSO household-based surveys,

especially GSO health-related surveys In addition to the

qualifications needed for interviewers, team leaders for the

GATS were experienced in using computers and handheld

(iPAQ) devices and had previous experience of working

with local authorities

Handheld computers were used for capturing data Each

interviewer and team leader had one iPAQ A real case file

containing addresses and names of the households assigned

to the interviewer was preloaded into the iPAQ before the

field work All the responses were entered by the

inter-viewer in the iPAQ, with the help of a stylus for touching

the key-pad on the screen Data collection was conducted

from 22 March 2010 to 13 May 2010 in all 63 provinces of

Vietnam

Study variables

In this work, the dependent variable was the status of

exposure to SHS at home The question in the

question-naire was ‘‘What is the frequency of tobacco smoking

inside your house (either family members or guests)?’’

Respondents who answered ‘‘daily’’ or ‘‘weekly’’ or

‘‘monthly’’ to the question were classified as people who

were exposed to SHS at home Independent variables were

gender, age, occupation, asset-based wealth index quintile

(this index was constructed by using household assets,

utilities, and housing construction as variables in

principal-components analysis and computing a wealth index for

each household), ethnicity, marital status, residence We

also included variables on the availability of smoking rules

at home and at work, and beliefs of the respondent about

the dangers of tobacco smoking and the dangers of

second-hand smoke (respondents who believed that breathing other

people’s smoke causes serious illness and specific disease

in non-smokers, i.e., heart disease in adults, lung illness in

children, lung cancer in adults, emphysema, low birth weight, premature birth)

Data analysis

Both descriptive and analytical statistical analysis was performed using Stata10 software (Stata Corporation) We conducted descriptive analysis of the status of exposure to SHS at home among non-smokers The analytical statistics were used for analysis of the status of exposure to SHS among non-smokers only Multivariate logistic regression modelling was performed to examine the association between patterns of exposure to second-hand smoke among non-smokers and relevant factors The sampling design was fully taken into consideration in the data analysis Weights were used in all computations A significance level of 0.05 was used

Results

Socio-demographic characteristics of the study population

Among the 11,142 sampled households, 10,383 were completely screened, giving a household response of 96.9% The household response was a little higher in rural areas than in urban areas (97.5 and 96.5%, respectively) Overall, only 0.6% of the selected households refused to respond to the survey Among 10,383 individuals selected from the completely screened households, 9,925 were completely interviewed, so the person-level response was 95.7% The person-level response was also a little higher in rural areas than in urban areas (96.3 and 95.0%, respec-tively) Overall, only 0.6% of the selected individuals refused to respond to the survey In GATS Vietnam 2010, the total response was 92.7% (93.9% in rural areas and 91.7% in urban sites) (Table 1)

Table2 presents sample size and population estimates

by selected socio-demographic characteristics The 9,925 completed interviews represented an estimated 64.3 million adults age 15 and over in Vietnam By age group, people age 25-44 made up the largest proportion (41.9%) and those 65 and above accounted for the smallest share (8.8%) Most of the study population reported having lower secondary school education (52.5%) or primary or less education (26.0%) People with a college degree or above made up 7.2% of the study population The main occupa-tion of the study populaoccupa-tion was Farmer (49.6%), followed

by Service/Sales (19.2%), and Production/Driving (12.9%) Other occupations were Manager/Professional (6.6%); Construction/Mining (5.2%); Office workers (2.0%); For-estry/Fishing (1.8%), and others (2.7%) By ethnicity,

84.5% of the population were Kinh people (the majority)

and the remaining 15.5% belonged to other ethnic minority

groups By marital status, 67.7% of the population were

married, 26.2% were still single, and the remainder (6.2%)

were separate/divorce/widow Two-thirds of people age 15

and over in Vietnam were living in rural areas

Prevalence of SHS at home

In Vietnam in 2010, 73.1% of adults aged 15 years and

above (representing approximately 47 million people)

reported that they were exposed to SHS at home at least

monthly.1 Considering non-smokers only (76.2% of the surveyed population or approximately 49 million people), the prevalence of exposure to SHS at home was 67.6% (equivalent to approximately 33 million non-smokers) Table3 shows the pattern of SHS exposure at home among the non-smoking population in the past 30 days according to selected socio-economic status The preva-lence of exposure to SHS at home among non-smoking males was lower than that among non-smoking females

Table 1 Number and percentage of households and persons interviewed, and response by residence (unweighted)—GATS Vietnam, 2010

Number Percent Number Percent Number Percent Selected household

Completed (HC) 5,525 92.2 5,158 94.4 10,383 93.2 Completed—No one eligible (HCNE) 1 0.0 0 0.0 1 0.0

No screening respondent (HNS) 2 0.0 5 0.0 7 0.1

Address not a dwelling (HAND) 29 0.5 18 0.2 47 0.4

Total households selected 5,670 100 5,472 100 11,142 100 Household response (HR) (%) b 96.5% 97.5% 96.9%

Selected person

Completed (PC) 4,958 94.9 4,967 96.3 9,925 95.6

Total number of sampled persons 5,225 100 5,158 100 10,383 100 Person-level response (PR) (%) c 95.0% 96.3% 95.7%

Total response (TR) (%)d 91.7% 93.9% 92.7%

a Other includes Nobody Home and any other result code not listed

b Calculate Household response (HR) by:

HCþHCNE

HCþHCNEþHINCþHNSþHRþHO

c Calculate Person-level response (PR) by:

PC100

PCþPINCþPRþPIþPO

d Calculate Total response (TR) by: (HR x PR)/100

An incomplete household interview (i.e., roster could not be finished) was considered a non-respondent to the GATS Thus, these cases (HINC) were not included in the numerator of the household response

A completed person interview (PC) includes respondents who had completed at least question E1 and who provided valid answers to questions B1/B2/B3 Respondents who did not meet these criteria were regarded as incomplete (PINC) non-respondents to GATS and thus, were not included in the numerator of the person-level response

1 Adults reporting that smoking inside their home occurs daily, weekly, or monthly.

(65.2% vs 68.8%, respectively) Exposure to SHS at home

decreased with increasing age The highest exposure to

SHS at home was among those age 15–24 (74.2%) and the

lowest was among those 65 and above (57.2%) The

prevalence of exposure to SHS at home among

non-smoking women aged 15–44 was 72.4% By education,

adults with primary education or less (71.5%) had the

highest prevalence of exposure to SHS at home and those

with college degrees or above (57.2%) had the lowest By

occupation, Forestry/Fishing people (77.5%) and Farmers (73.5%) had the highest exposure to SHS at home, whereas Manager/Professional staff had the lowest (48.3%) There was no specific pattern of exposure to SHS at home and at work by economic status However, the prevalence of exposure to SHS at home among people in the higher quintile was significantly higher than that among those in the lower quintile (69.7% in quintile 1 and 55.6% in quintile 5) By ethnicity, Kinh people had lower prevalence

of exposure to SHS at home compared with other ethnic minority groups There was no statistically significant difference in the prevalence of exposure to SHS at work by marital status By residence, people living in rural areas (72.0%) were more likely to be exposed than those living

in urban areas (57.7%)

Table4lists regulations on tobacco smoking at home in Vietnam Only 10.7% of the study respondents reported that smoking is never allowed in their home Most house-holds had no indoor smoking rule (62.7%)

Correlates of SHS at home

Logistic regression models were performed (presented as odds ratio (OR) and corresponding 95% CI) to examine the association between status of exposure to SHS among non-smokers at home and selected socio-demographic factors Because education level was reported only among respondents 25? years old, two models were constructed:

1 Model a: for all the study subjects (all aged 15 years and over) education was excluded; and

2 Model b: for those aged 25 years and over and education was included as an independent variable The models showed that the significant correlates of the status of exposure to SHS at home were as listed in Table5

• Gender: Females were more likely than males to be exposed to SHS at home

• Age: The prevalence of exposure to SHS at home decreased with increasing age

• Occupation: People working as Service/Sales, Farmer, and Production/Driving employees were more likely than Manager/Professional staff to be exposed to SHS

at home

• Ethnicity: People belong to ethnic minority groups were more likely than Kinh people to be exposed to SHS at home

• Residence: People living in rural areas were more likely than those living in urban areas to be exposed to SHS at home

• Smoking restriction in the home: Exposure to SHS at home was significantly prevalent in households where smoking is allowed

Table 2 Distribution of study subjects by selected

socio-demo-graphic characteristics—GATS Vietnam, 2010

Characteristic Sample

size

Weighted number

Weighted %

Gender

Male 4,356 31,258,108 48.6

Female 5,569 33,062,657 51.4

Age

15–24 1,656 16,637,021 25.9

25–34 2,053 12,661,740 19.6

35–44 2,198 14,281,840 22.2

45–54 1,867 9,657,483 15.0

55–64 1,019 5,407,631 8.4

[ 64 1,132 5,675,050 8.8

Education –

Primary 2,034 12,377,177 26.0

Secondary 3,981 25,031,220 52.5

High school 1,023 6,793,646 14.3

College, university 1,227 3,447,042 7.2

Occupation –

Manager/Professional 845,000 3,120,000 6.6

Office worker 220,000 916,000 2.0

Service/Sales 1,589,000 8,991,000 19.2

Farming 3,069,000 23,255,000 49.6

Forestry/Fishing 120,000 867,000 1.8

Construction/Mining 317,000 2,442,000 5.2

Production/Driving 834,000 6,063,000 12.9

Other 248,000 1,272,000 2.7

Ethnicity

Kinh (the majority) 8,555 54,368,513 84.5

Others 1,370 9,952,252 15.5

Marital status

Single 1,882 16,846,557 26.2

Married 7,078 43,452,453 67.6

Separate 67 218,162 0.3

Divorce 152 556,605 0.9

Widow 740 3,214,116 5.0

Urban 4,958 19,724,648 30.7

Rural 4,967 44,596,117 69.3

Total 9,925 64,320,765 100

• Education: People with lower educational level were more likely to be exposed to SHS at home

Discussion

The findings from this study showed that very many non-smokers in Vietnam were exposed to SHS Up to 67.6% of non-smokers (equivalent to approximately 33 million people) aged 15 and above were exposed to SHS at home The Vietnam National Health Survey 2001–2002 also reported that 63% of households in Vietnam had at least one smoker [14] The prevalence of exposure to SHS at home in Vietnam similar to that reported in the GATS conducted in China (67.3%) [17], but was higher than the corresponding figures found in the Philippines (44.8%) [18] and in Thailand (39.1%) [19]

The high prevalence of exposure to SHS at home in Vietnam can be explained by the fact that tobacco control

in the country has not yet prioritized a focus on smoke-free homes Furthermore, even though smoking is strictly pro-hibited in indoor workplaces and public places, for exam-ple schools, kindergartens, health facilities, libraries, cinemas, theatres, and community cultural centers, and on

Table 3 Pattern of SHS at home among non-smoking populations

by socio-demographic characteristics—GATS Vietnam, 2010 (n =

7563)

Characteristic Prevalence of

SHS at home (%)

95% CI of the prevalence Lower bound

(%)

Upper bound (%) Gender

Male 65.2 62.7 67.1

Female 68.8 67.3 70.3

Age

15–24 74.2 71.5 76.9

25–34 68.3 65.5 71.0

35–44 68.2 65.5 71.0

45–54 64.8 61.7 67.9

55–64 57.5 53.2 61.8

[ 64 57.2 53.4 61.1

Education

Primary 71.5 68.9 74.1

Secondary 66.8 64.7 68.8

High school 56.6 52.4 60.9

College, university 43.7 40.0 47.4

Job

Manager/

Professional

48.3 42.9 53.7

Office worker 58.3 48.7 67.2

Service/Sales 68.9 65.7 71.9

Farming 73.5 71.0 75.9

Forestry/Fishing 77.5 62.7 87.5

Construction/

Mining

66.2 55.4 75.5

Production/Driving 67.8 62.4 72.8

Others 63.0 53.5 71.6

Asset quintile

Quintile 1 69.7 66.9 72.5

Quintile 2 74.0 71.2 76.7

Quintile 3 73.8 70.7 76.8

Quintile 4 65.1 62.2 68.1

Quintile 5 55.6 52.8 58.5

Marital status

Single 70.9 68.2 73.6

Married 68.0 66.5 69.5

Separate 50.1 33.7 66.5

Divorce 48.2 36.6 59.8

Widow 51.5 46.8 56.3

Area

Urban 57.7 55.9 59.5

Rural 72.0 70.3 73.7

Smoking is allowed at home

Yes 88.5 85.6 91.4

Table 3 continued Characteristic Prevalence of

SHS at home (%)

95% CI of the prevalence Lower bound

(%)

Upper bound (%) Smoking is allowed at work

Yes 67.0 58.2 75.7 Believed smoking causes stroke, heart attack, and lung cancer

Yes 65.1 63.4 66.9 Believed SHS is dangerous

Yes 66.8 65.4 68.2

Table 4 Regulations on tobacco smoking at home in Vietnam, GATS 2010 (n = 7,563)

Description Urban

(%)

Rural (%)

Overall (%) Indoor smoking is allowed 7.7 10.8 9.8 Indoor smoking is not allowed but

exceptions

19.9 15.1 16.5

Indoor smoking is never allowed 16.5 8.2 10.7

No indoor smoking rule 55.7 65.9 62.7

Do not know, no response 0.3 0.2 0.2

public transport (according to the government’s Decision

No 1,315/QÐ-TTg), the prevalence of exposure to SHS at work and in public places were still very high [20] Vio-lation of the smoke-free workplace and public places reg-ulation has been shown to have negative effect on smoking behaviour in private settings [21] Legislation should consider the issue of the smoke-free home in the near future to protect children and vulnerable household mem-bers from SHS in the home Community health education programmes to raise public awareness and practice are also needed to encourage families to make their homes smoke-free, which would protect children and other family members from the dangers of second-hand smoke Scien-tific evidence has shown that voluntary smoke-free home policies reduce exposure of children and adult non-smokers

to second-hand smoke, reduce smoking in adults, and seem

to reduce smoking in youths [22]

The GATS Vietnam 2010 revealed that females had higher prevalence of exposure to SHS at home than males and this finding implied that even though the prevalence of smoking among Vietnamese women was low, they have still been greatly exposed to the hazards of tobacco smoke This phenomenon could be explained by the fact that many non-smoking women in Vietnam live with a male smoker and they spend most of their time at home This finding is consistent with a study from China [23] Our study revealed that the prevalence of exposure to SHS at home among non-smoking women of reproductive age was high (72.4%) There is much published research, and studies are now confirming that inhaling second hand cigarette smoke also causes reproduction problems [1]

Our study also found that other disadvantaged people in Vietnam, for example those belonging to ethnic minority groups, rural dwellers, and people with lower education were more likely to be exposed to SHS at home This

Table 5 Results from logistic regression analysis of the association

between exposure to SHS at home with selected socio-demographic

factors, among non-smokers—Vietnam GATS, 2010

Characteristic Model 1a (Education

excluded, people aged 15?) OR (95% CI)

Model 1b (Education included, people aged 25?) OR (95% CI) Gender

Female 1.2 [1.1–1.4]* 1.2 [1.1–1.4]*

Age group

Aged 25–34 0.6 [0.5–0.8] 1.00

Aged 35–44 0.6 [0.4–0.8]* 0.9 [0.7–1.0]

Aged 45–54 0.5 [0.4–0.7]* 0.7 [0.6–0.9]*

Aged 55–64 0.3 [0.2–0.5]* 0.5 [0.4–0.6]*

Aged [64 0.4 [0.3–0.5]* 0.4 [0.3–0.6]*

Occupation

Manager/Professional 1.00 1.00

Office worker 1.4 (0.9–2.2) 1.3 (0.8–2.0)

Service/Sales 2.1 (1.6–2.7)* 1.7 (1.2–2.4)*

Farming 2.0 (1.5–2.6)* 1.6 (1.1–2.3)*

Forestry/Fishing 2.1 (1.0–4.4) 1.4 (0.6–3.1)

Construction/Mining 1.8 (1.0–3.1) 1.6 (0.9–2.9)

Production/Driving 1.8 (1.3–2.4)* 1.6 (1.1–2.4)*

Others 1.4 (0.9–2.1) 1.1 (0.7–1.8)

Asset quintile

Quintile 2 1.4 [1.1–1.7] 1.2 [1–1.6]

Quintile 3 1.5 [1.2–1.8] 1.2 [1–1.6]

Quintile 4 1.3 [1.0–1.6] 1 [0.8–1.3]

Quintile 5 1.1 [0.9–1.4] 1 [0.8–1.3]

Ethnicity

Kinh (the majority) 1.00 1.00

Others 1.3 [1.1–1.7]* 1.4 [1.1–1.8]*

Marital status

Single 0.9 [0.7–1.2] 0.8 [0.6–1.1]

Separate 0.5 [0.3–0.9] 0.5 [0.2–0.9]

Divorce 0.5 [0.3–0.8] 0.5 [0.3–0.7]

Widow

Area

Smoking is allowed at home

Smoking is allowed at work

Believed smoking causes stroke, heart attack, and lung cancer.

Table 5 continued

Characteristic Model 1a (Education

excluded, people aged 15?) OR (95% CI)

Model 1b (Education included, people aged 25?) OR (95% CI) Believed SHS is dangerous

Education

College, university – 0.4 [0.3–0.6]*

* p \ 0.05

indicates there is an inequity problem in exposure to SHS

at home in Vietnam This finding is similar to those from

studies from China [23,24], USA [25], and Spain [26], and

implies that tobacco control policies should pay special

consideration to these disadvantaged populations

Our study demonstrated the effect of smoking restriction

in reducing the prevalence of exposure to SHS at home

Similar findings were also obtained in studies in China [23,

24] Because many households in Vietnam still have no

regulations restricting smoking at home, a smoke-free

household policy is necessary to reduce household SHS

exposure In fact, the GATS Vietnam showed that most

adults supported smoke-free home regulations [27]

Pro-motion of smoke-free homes may be an important area to

emphasize in a tobacco control campaign

Our study has several limitations First, data from the

GATS on exposure to SHS are self-reported and no

objective measurement of levels of exposure to SHS was

conducted Second, estimates of SHS exposure discussed

here did not consider duration of exposure Third, the

cross-sectional design of the study does not enable us to

establish any causal connection

In summary, the GATS Vietnam 2010 has shown that a

high percentage of people are exposed to second-hand

smoke at home The significant correlates of the status of

exposure to SHS at home were female gender, ethnic

minority, low education, and lack of smoking restriction at

home Because smoke-free homes have not been included

in tobacco-control policies, advocating of smoke-free

homes initiatives is urgently needed Special considerations

should be given to disadvantaged people, because they are

more likely than the better-off to be exposed to SHS at

home, and to promoting community health-education

pro-grams to raise public awareness of the harm of tobacco use

and exposure to tobacco smoke Further studies are also

needed to overcome the limitations of this study, for

example a study with objective measurement of level of

exposure to SHS (blood or urine cotinine) and study of

SHS exposure among children, women, the poor, etc

Acknowledgments This study was funded by the Bloomberg

Phi-lanthropies We highly appreciate the contributions to the success of

the survey made by the Centers for Disease Control and Prevention in

Atlanta, the CDC Foundation, the World Health Organization, the

General Statistics Office of Vietnam, and Hanoi Medical University.

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