Table 1 Operational definition of variables used in the study

Age at menarche (in years)

Age at menarche indicates the age of onset of the first menstrual period of a woman. It is divided into four categories- ‘less than 12 years’ (1); ‘13–15 years’ (2); ‘more than 16 years’ (3). Some of them don’t remember the age; they are coded as ‘don’t know’ (0)

Age at marriage (in years)

Age at marriage is divided into 3 categories- ‘marriage before 18 years’ (0), ‘marriage after 18 years’ (1), and ‘not married’ (2)

Respondent’s education

Education level is categorized into four groups- ‘no education’ (0), ‘primary’ (1), ‘secondary’ (2) and ‘higher’ (3)

Household wealth status

The wealth index is a composite index of household amenities and assets; it indicates the socioeconomic condition of a household. In NFHS-5, every household is given a score based on the number of consumer goods they own. A total of 33 assets and housing characteristics were taken into consideration to prepare a factor score using Principal Component Analysis. Thereafter this factor score is divided into five equal categories, − ‘poorest’ (1); ‘poorer’ (2); ‘middle’ (3); ‘richer’ (4); ‘richest’ (5) each with 20% of the population.

Social groups

Social groups are divided into 4 categories- ‘Scheduled Caste’ (1), ‘Scheduled Tribe’ (2), ‘Other Backward Classes’ (3), ‘Others’ (General) (4)

Religion

Religion is divided into four categories – ‘Hindu’ (1); ‘Muslim’ (2); ‘Christian’ (3) ‘Others’ (4). Others include all religious groups other than Hindu, Muslim, and Christian.

Region of residence

To construct this variable, Indian states are grouped into 6 categories. ‘Northern’ (1) includes Jammu & Kashmir, Ladakh, Himachal Pradesh, Punjab, Rajasthan, Haryana, Uttarakhand, Chandigarh (Union Territory - UT) and Delhi; ‘central’ (2) includes the states of Uttar Pradesh, Madhya Pradesh and Chhattisgarh; ‘eastern’ (3) includes the states of Bihar, Jharkhand, West Bengal and Odisha; ‘western’ (4) includes the states of Gujarat, Maharashtra, Goa and UTs of Dadra & Nagar Haveli and Daman & Diu; ‘southern’ (5) includes the states of Kerala, Karnataka, Andhra Pradesh, Tamil Nadu and the UTs of Andaman & Nicobar Islands, Pondicherry and Lakshadweep); ‘north-eastern’ (6) includes the states of Sikkim, Assam, Meghalaya, Manipur, Mizoram, Nagaland, Tripura, and Arunachal Pradesh. This classification has been used by the NFHS-5 report [31]

Type of home

We have recoded the variable v150 (labelled as “relationship to household head” in NFHS-5 ‘individual’ dataset to generate a categorical variable, ‘Type of home’. Based on the respondent’s relationship with the household head, four categories were created, − marital home, natal home, other home, and household head. ‘Marital home’ (1) includes wife, daughter-in-law, parent, parent-in-law, co-spouse, niece by marriage, sister-in-law; ‘natal home’ (2) includes daughter, grandchild, sister, other relatives, niece by blood, niece; ‘other’s home’ (3) includes domestic servant, adopted/foster child, non-relatives; and ‘head of the household’ (4) respondents who are household head themselves [26].

Working status

Working status indicates the employment condition of the respondent. A dichotomous variable is formed: ‘not working’ (1) and ‘working’ (2)

Exposure to mass media

Three questions were asked to women in NFHS-5 survey. They are i) how often they read newspaper/magazines, ii) how often they watch television, and iii) how often they listen to radio. The responses are ‘almost every day’, at least once a week, less than once a week and not at all. Based on these responses a composite index is computed and divided into four categories: ‘no exposure’ (0) if the respondent is not exposed to any mass media; ‘low exposure’ (1) if a respondent is exposed to any one type of mass media; ‘medium exposure’ (2) if the respondent is exposed to any two types of mass media; ‘high exposure’ (3) if the respondent is exposed to all three types of mass media.

Discussed menstrual hygiene with healthcare workers (in last 3 months)

Questions were asked to the respondents in NFHS-5, they are- i) in the last 3 months, if the respondent has met with any health worker- including an auxiliary nurse midwife (ANM), accredited social health activist (ASHA), Anganwadi worker (AWW), also known as Integrated Child Development Services worker, multipurpose worker (MPW), or any other community health worker; and ii) if they have discussed about menstrual hygiene during the meeting. If respondent did not discuss menstrual hygiene with healthcare workers, then they are coded as 0, if discussed 1.

Own a bank account

Whether a respondent owns a bank/savings account by herself – ‘yes’ (1); ‘no’ (0)

Own a mobile phone

Whether a respondent owns a bank/savings account by herself – ‘yes’ (1); ‘no’ (0)

Proportion of women with secondary level of education in PSU

The proportion of women with secondary level of education in PSUs variable has been categorized into three groups, ‘0–25% of women with secondary level of education in PSUs’ (1); ‘26–50% of women with secondary level of education in PSU’ (2); and ‘more than 50% women with secondary level of education in PSU’ (3)

Proportion of poor women in PSU

The proportion of poor women in PSUs variable has been categorized into three groups, ‘0–25% of poor women living in PSUs’ (1); ‘26–50% of poor women living in PSUs’ (2); and ‘more than 50% poor women living in PSUs’ (3)

Proportion of SC/ST women in PSU

The proportion of SC/ST women in PSUs, this variable has been categorized into three groups, ‘0–25% of SC/ST women living in PSUs’ (1); ‘26–50% of SC/ST women living in PSUs’ (2); and ‘more than 50% SC/ST women living in PSUs’ (3)